FACTOID # 97: The top five countries of origin for refugees are all in Africa.
 
 Home   Encyclopedia   Statistics   Countries A-Z   Flags   Maps   Education   Forum   FAQ   About 
 
WHAT'S NEW
RECENT ARTICLES
More Recent Articles »
 

For other uses, see ZFS (disambiguation).
ZFS
Developer Sun Microsystems
Full name ZFS
Introduced November 2005 (OpenSolaris)
Partition identifier
Structures
Directory contents Extensible hash table
File allocation
Bad blocks
Limits
Max file size 16 EiB
Max number of files 248
Max filename size 255 bytes
Max volume size 16 EiB
Allowed characters in filenames
Features
Dates recorded
Date range
Date resolution
Forks Yes (called Extended Attributes)
Attributes POSIX
File system permissions POSIX
Transparent compression Yes
Transparent encryption Yes (currently alpha)[1]
Supported operating systems Sun Solaris, Apple Mac OS X 10.5, FreeBSD, Linux via FUSE

In computing, ZFS is a file system originally created by Sun Microsystems for the Solaris Operating System. The features of ZFS include high storage capacity, integration of the concepts of filesystem and volume management, a novel on-disk structure, lightweight instances, and easy storage pool management. ZFS is implemented as open-source software, licensed under the Common Development and Distribution License (CDDL). ZFS may refer to: ZFS, a file system developed by Sun Microsystems z/OS Distributed File Service zSeries File System, a file system developed by IBM and included in the z/OS operating system zFS, an experimental file system from IBM based on object storage ZFS-NAS, a file system... For other uses, see Software developer (disambiguation). ... Sun Microsystems, Inc. ... OpenSolaris is an open source project created by Sun Microsystems to build a developer community around Solaris Operating System technology. ... In computer engineering, hard disk drive partitioning is the creation of logical divisions upon a hard disk that allows one to apply operating system-specific logical formatting. ... EIB is an acronym that may stand for: European Investment Bank, the European Unions financing institution Even in Blackouts, an American band Expert Infantryman Badge, a military badge of the United States Army Exbibit (Eib), a unit of information used, for example, to quantify computer memory or storage capacity... EIB is an acronym that may stand for: European Investment Bank, the European Unions financing institution Even in Blackouts, an American band Expert Infantryman Badge, a military badge of the United States Army Exbibit (Eib), a unit of information used, for example, to quantify computer memory or storage capacity... In computer file systems, a fork is additional data associated with a file system object. ... Extended file attributes is a file system feature that enables users to associate with computer files metadata not interpreted by the filesystem, whereas regular attributes have a purpose strictly defined by the filesystem (such as permissions or records of creation and modification times). ... POSIX or Portable Operating System Interface[1] is the collective name of a family of related standards specified by the IEEE to define the application programming interface (API) for software compatible with variants of the Unix operating system. ... Most modern file systems have methods of administering permissions or access rights to specific users and groups of users. ... Filesystem-level encryption, is a form of disk encryption where individual files or directories are encrypted by the file system, in contrast to full disk encryption where the entire partition or disk, where the file system resides, is encrypted. ... Software development stages In computer programming, development stage terminology expresses how the development of a piece of software has progressed and how much further development it may require. ... An operating system (OS) is the software that manages the sharing of the resources of a computer and provides programmers with an interface used to access those resources. ... Solaris is a computer operating system developed by Sun Microsystems. ... Mac OS X version 10. ... FreeBSD is a Unix-like free operating system descended from AT&T UNIX via the Berkeley Software Distribution (BSD) branch through the 386BSD and 4. ... This article is about operating systems that use the Linux kernel. ... Filesystem in Userspace (FUSE) is a Free (GPL and LGPLed) Unix kernel module that allows non-privileged users to create their own file systems without the need to write any kernel code. ... For the formal concept of computation, see computation. ... For library and office filing systems, see Library classification. ... Sun Microsystems, Inc. ... Solaris is a computer operating system developed by Sun Microsystems. ... Introduction and Definition In the context of computer operating systems, volume is the term used to describe a single accessible storage area with a single filesystem, typically (though not necessarily) resident on a single partition of a hard disk. ... Open source software is computer software for which the human-readable source code is made available under a copyright license (or arrangement such as the public domain) that meets the Open Source Definition. ... Common Development and Distribution License (CDDL) is an open source and Free software license, produced by Sun Microsystems, based on the Mozilla Public License (MPL), version 1. ...

Contents

History

ZFS was designed and implemented by a team at Sun led by Jeff Bonwick. It was announced on September 14, 2004.[2] Source code for ZFS was integrated into the main trunk of Solaris development on October 31, 2005[3] and released as part of build 27 of OpenSolaris on November 16, 2005. Sun announced that ZFS was included in the 6/06 update to Solaris 10 in June 2006, one year after the opening of the OpenSolaris community.[4] Jeff Bonwick is a Distinguished Engineer at Sun Microsystems. ... is the 257th day of the year (258th in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... is the 304th day of the year (305th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... OpenSolaris is an open source project created by Sun Microsystems to build a developer community around Solaris Operating System technology. ... is the 320th day of the year (321st in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ...


The name originally stood for "Zettabyte File System", but is now a pseudo-initialism.[5] A zettabyte (derived from the SI prefix zetta-) is a unit of information or computer storage equal to one sextillion (one long scale trilliard) bytes. ... A pseudo-acronym (or empty acronym[1]) is an apparent acronym or other abbreviation which doesnt stand for anything, or cannot be officially expanded to some meaning. ...


Storage pools

Unlike traditional file systems, which reside on single devices and thus require a volume manager to use more than one device, ZFS filesystems are built on top of virtual storage pools called zpools. A zpool is constructed of virtual devices (vdevs), which are themselves constructed of block devices: files, hard drive partitions, or entire drives, with the last being the recommended usage.[6] Block devices within a vdev may be configured in different ways, depending on needs and space available: non-redundantly (similar to RAID 0), as a mirror (RAID 1) of two or more devices, as a RAID-Z group of three or more devices, or as a RAID-Z2 group of four or more devices.[7] The storage capacity of all vdevs is available to all of the file system instances in the zpool. A virtual device in Unix is a file such as /dev/null or /dev/urandom, that is treated as a device, as far as user level software is concerned, but is generated by the kernel without reference to hardware. ... A device node, device file, or device special file, a type of special file, featured on many Unix-like operating systems. ... In computer operating systems, disk partitioning is the creation of logical divisions upon a hard disk that allows one to apply operating system-specific logical formatting. ... The standard RAID levels are a basic set of RAID configurations and employ striping, mirroring, or parity. ... The standard RAID levels are a basic set of RAID configurations and employ striping, mirroring, or parity. ... Main article: RAID Although all implementations of RAID differ from the idealized specification to some extent, some companies have developed non-standard RAID implementations that differ substantially from the rest of the crowd. ... Main article: RAID Although all implementations of RAID differ from the idealized specification to some extent, some companies have developed non-standard RAID implementations that differ substantially from the rest of the crowd. ...


A quota can be set to limit the amount of space a file system instance can occupy, and a reservation can be set to guarantee that space will be available to a file system instance. A disk quota is a limit set by a system administrator that restricts certain aspects of file system usage on modern operating systems. ...


Capacity

ZFS is a 128-bit file system, so it can store 18 billion billion (18.4 × 1018) times more data than current 64-bit systems. The limitations of ZFS are designed to be so large that they will not be encountered in practice for some time. Some theoretical limits in ZFS are: In computer architecture, 128-bit integers, memory addresses, or other data units are those that are at most 128 bits wide. ... In computing, a 64-bit component is one in which data are processed or stored in 64-bit units (words). ...

  • 264 — Number of snapshots of any file system[8]
  • 248 — Number of entries in any individual directory[9]
  • 16 EiB (264 bytes) — Maximum size of a file system
  • 16 EiB — Maximum size of a single file
  • 16 EiB — Maximum size of any attribute
  • 256 ZiB (278 bytes) — Maximum size of any zpool
  • 256 — Number of attributes of a file (actually constrained to 248 for the number of files in a ZFS file system)
  • 256 — Number of files in a directory (actually constrained to 248 for the number of files in a ZFS file system)
  • 264 — Number of devices in any zpool
  • 264 — Number of zpools in a system
  • 264 — Number of file systems in a zpool

If a billion computers each filled a billion individual file systems per second, the time required to reach the limit of the overall system would be almost 1,000 times the estimated age of the universe. In computer file systems, a snapshot is a copy of a set of files and directories as they were at a particular point in the past. ... EIB is an acronym that may stand for: European Investment Bank, the European Unions financing institution Even in Blackouts, an American band Expert Infantryman Badge, a military badge of the United States Army Exbibit (Eib), a unit of information used, for example, to quantify computer memory or storage capacity... A zebibyte (a contraction of zetta binary byte) is a unit of information or computer storage, commonly abbreviated ZiB. 1 zebibyte = 270 bytes = 1,180,591,620,717,411,303,424 bytes = 1,024 exbibytes The zebibyte is closely related to the zettabyte, which can either be a (deprecated) synonym... The age of the universe, in Big Bang cosmology, refers to the time elapsed between the Big Bang and the present day. ...


Project leader Bonwick said, "Populating 128-bit file systems would exceed the quantum limits of earth-based storage. You couldn't fill a 128-bit storage pool without boiling the oceans."[2] Later he clarified:

“ Although we'd all like Moore's Law to continue forever, quantum mechanics imposes some fundamental limits on the computation rate and information capacity of any physical device. In particular, it has been shown that 1 kilogram of matter confined to 1 liter of space can perform at most 1051 operations per second on at most 1031 bits of information [see Seth Lloyd, "Ultimate physical limits to computation." Nature 406, 1047-1054 (2000)]. A fully populated 128-bit storage pool would contain 2128 blocks = 2137 bytes = 2140 bits; therefore the minimum mass required to hold the bits would be (2140 bits) / (1031 bits/kg) = 136 billion kg.
To operate at the 1031 bits/kg limit, however, the entire mass of the computer must be in the form of pure energy. By E=mc², the rest energy of 136 billion kg is 1.2x1028 J. The mass of the oceans is about 1.4x1021 kg. It takes about 4,000 J to raise the temperature of 1 kg of water by 1 degree Celsius, and thus about 400,000 J to heat 1 kg of water from freezing to boiling. The latent heat of vaporization adds another 2 million J/kg. Thus the energy required to boil the oceans is about 2.4x106 J/kg * 1.4x1021 kg = 3.4x1027 J. Thus, fully populating a 128-bit storage pool would, literally, require more energy than boiling the oceans.[10]		 ”

Gordon Moores original graph from 1965 Growth of transistor counts for Intel processors (dots) and Moores Law (upper line=18 months; lower line=24 months) For the observation regarding information retrieval, see Mooers Law. ... For a less technical and generally accessible introduction to the topic, see Introduction to quantum mechanics. ... Kg redirects here. ... The liter (spelled liter in American English and litre in Commonwealth English) is a unit of volume. ... The joule (IPA: or ) (symbol: J) is the SI unit of energy. ... The degree Celsius (symbol: °C) is an SI derived unit of temperature. ...

Copy-on-write transactional model

ZFS uses a copy-on-write transactional object model. All block pointers within the filesystem contain a 256-bit checksum of the target block which is verified when the block is read. Blocks containing active data are never overwritten in place; instead, a new block is allocated, modified data is written to it, and then any metadata blocks referencing it are similarly read, reallocated, and written. To reduce the overhead of this process, multiple updates are grouped into transaction groups, and an intent log is used when synchronous write semantics are required. Copy-on-write (sometimes referred to as COW) is an optimization strategy used in computer programming. ... In computer science, transaction processing is information processing that is divided into individual, indivisible operations, called Each transaction must succeed or fail as a complete unit; it cannot remain in an intermediate state. ... In the computing discipline object model has two related but distinct meanings: 1. ... A checksum is a form of redundancy check, a simple way to protect the integrity of data by detecting errors in data that are sent through space (telecommunications) or time (storage). ... Metadata is data about data. ...


Snapshots and clones

An advantage of copy-on-write is that when ZFS writes new data, the blocks containing the old data can be retained, allowing a snapshot version of the file system to be maintained. ZFS snapshots are created very quickly, since all the data composing the snapshot is already stored; they are also space efficient, since any unchanged data is shared among the file system and its snapshots. In computer file systems, a snapshot is a copy of a set of files and directories as they were at a particular point in the past. ...


Writeable snapshots ("clones") can also be created, resulting in two independent file systems that share a set of blocks. As changes are made to any of the clone file systems, new data blocks are created to reflect those changes, but any unchanged blocks continue to be shared, no matter how many clones exist.


Dynamic striping

Dynamic striping across all devices to maximize throughput means that as additional devices are added to the zpool, the stripe width automatically expands to include them; thus all disks in a pool are used, which balances the write load across them. The term Data striping refers to the segmentation of logically sequential data, such as a single file, so that segments can be written to multiple physical devices (usually disk drives) in a round-robin fashion. ...


Variable block sizes

ZFS uses variable-sized blocks of up to 128 kilobytes. The currently available code allows the administrator to tune the maximum block size used as certain workloads do not perform well with large blocks. Automatic tuning to match workload characteristics is contemplated.[citation needed]


If data compression is enabled, variable block sizes are used. If a block can be compressed to fit into a smaller block size, the smaller size is used on the disk to use less storage and improve IO throughput (though at the cost of increased CPU use for the compression and decompression operations). Source coding redirects here. ...


Lightweight filesystem creation

In ZFS, filesystem manipulation within a storage pool is easier than volume manipulation within a traditional filesystem; the time and effort required to create or resize a ZFS filesystem is closer to that of making a new directory than it is to volume manipulation in some other systems.


Additional capabilities

  • Explicit I/O priority with deadline scheduling.
  • Claimed globally optimal I/O sorting and aggregation.
  • Multiple independent prefetch streams with automatic length and stride detection.
  • Parallel, constant-time directory operations.
  • End-to-end checksumming, allowing data corruption detection (and recovery if you have redundancy in the pool).
  • Intelligent scrubbing and resilvering.[11]
  • Load and space usage sharing between disks in the pool.[12]
  • Ditto blocks: Metadata is replicated inside the pool, two or three times (according to metadata importance).[13] If the pool has several devices, ZFS tries to replicate over different devices. So a pool without redundancy can lose data if you find bad sectors, but metadata should be fairly safe even in this scenario.
  • ZFS design (copy-on-write + superblocks) is safe when using disks with write cache enabled, if they support the cache flush commands issued by ZFS. This feature provides safety and a performance boost compared with some other filesystems.
  • When entire disks are added to a ZFS pool, ZFS automatically enables their write cache. This is not done when ZFS only manages discrete slices of the disk, since it doesn't know if other slices are managed by non-write-cache safe filesystems, like UFS.
  • Filesystem encryption is supported, though is currently in an alpha stage.[1]

The UNIX file system (UFS) is a file system used by many Unix and Unix-like operating systems. ...

Cache management

ZFS also uses the ARC, a new method for cache management, instead of the traditional Solaris virtual memory page cache. Adaptive Replacement Cache (ARC) is a cache management algorithm with better performance[1] than LRU (Least Recently Used) developed[2] at the IBM Almaden Research Center. ...


Limitations

ZFS does not support per-user or per-group quotas. Instead, it is possible to create user-owned filesystems, each with its own size limit. Intrinsically, there is no practical quota solution for the file systems shared among several users (such as team projects, for example), where the data cannot be separated per user, although it could be implemented on top of the ZFS stack.


Capacity expansion is normally achieved by adding groups of disks as vdev (stripe, RAID-Z, RAID-Z2, or mirrored). Newly written data will dynamically start to use all available vdevs. It is also possible to expand the array by iteratively swapping each drive in the array with a bigger drive and waiting for ZFS to heal itself — the heal time will depend on amount of stored information, not the disk size. If a snapshot is taken during this process, it will cause the heal to be restarted.


It is currently not possible to reduce the number of vdevs in a pool nor otherwise reduce pool capacity. However, it is currently being worked on by the ZFS team.


It is not possible to add a disk to a RAID-Z or RAID-Z2 vdev. This feature appears very difficult to implement. Main article: RAID Although all implementations of RAID differ from the idealized specification to some extent, some companies have developed non-standard RAID implementations that differ substantially from the rest of the crowd. ...


Reconfiguring storage requires copying data offline, destroying the pool, and recreating the pool with the new policy.


ZFS is not a native cluster, distributed, or parallel file system and cannot provide concurrent access from multiple hosts as ZFS is a local file system. Sun's Lustre distributed filesystem will adapt ZFS as back-end storage for both data and metadata in version 1.8, which will be released in Q2 2008. [14] An example of a Computer cluster A computer cluster is a group of tightly coupled computers that work together closely so that in many respects they can be viewed as though they are a single computer. ... For other uses, see Distributed file system (disambiguation). ... For the protocol of this name, see Network File System (protocol). ... Lustre is an Open Source file system for Network-attached storage, generally used for large scale cluster computing. ...


It is currently not possible to natively nest vdevs within a zpool — to create, for example, a non-redundant pool of RAID-Z vdevs (similar to a RAID 5+0). To gain performance and/or additional redundancy the Standard RAID levels can be combined to create hybrid or Nested RAID levels. ...


Solaris implementation issues

This article or section needs to be updated.
Please update the article to reflect recent events, and remove this template when finished.

The current ZFS implementation (Solaris 10 11/06) has some issues administrators should know before deploying it. Many of these issues are scheduled to be addressed in future releases. Image File history File links This is a lossless scalable vector image. ...

  • ZFS root filesystem support is currently set to off on Solaris 10 default installations, since the standard installer still does not fully support ZFS roots. The ZFS Boot project successfully added boot support to the OpenSolaris project in March 2007.[15][16] Bootable ZFS file systems are only available for x86 systems, and must be done with scripts or manually. As of February 2008, Sun has said that supported ZFS boot for both SPARC and x86 systems is planned for a Solaris 10 update in late 2008.
  • If a Solaris Zone is put on ZFS, the system cannot be upgraded; the OS will need to be reinstalled. This issue is planned to be addressed in a Solaris 10 update in 2007[citation needed].[update needed]
  • A file "fsync" will commit to disk all pending modifications on the filesystem. That is, an "fsync" on a file will flush out all deferred (cached) operations to the filesystem (not the pool) in which the file is located. This can make some fsync() slow when running alongside a workload which writes a lot of data to filesystem cache.[17] The issue is currently fixed in Solaris Nevada.
  • New vdevs can be added to a storage pool, but they cannot be removed. A vdev can be exchanged for a bigger one, but it cannot be removed (even if the size to be removed is less than the pool's unused space). The ability to shrink a zpool is a work in progress, currently targeted for a Solaris 10 update in late 2007.[update needed]
  • ZFS encourages creation of many filesystems inside the pool (for example, for quota control), but importing a pool with thousands of filesystems is a slow operation (can take minutes).
  • ZFS uses a lot of CPU when doing small writes (for example, a single byte). There are two root causes, currently being worked on: a) Translating from znode to dnode is slower than necessary because ZFS doesn't use translation information it already has, and b) Current partial-block update code is very inefficient.[18]
  • ZFS copy-on-write operation can degrade on-disk file layout (file fragmentation) when files are modified, decreasing performance.
  • ZFS blocksize is configurable per filesystem, currently 128 KB by default. Reads or writes which are smaller than the block size suffer a performance penalty. If your workload reads/writes data in fixed sizes (blocks), for example a database, you should (manually) configure ZFS blocksize equal to the application blocksize, for better performance and to conserve cache memory and disk bandwidth.
  • ZFS only offlines a faulty hard disk if it can't be opened. Read/write errors or slow/timed-out operations do not currently cause a disk to be marked as faulty. This is fixed in Solaris Nevada via 6520519.
  • When listing ZFS space usage, the "used" column only shows non-shared usage; if some data is shared (for example, between snapshots), it cannot be determined how much unique data is held by a particular snapshot, making it hard to tell, for example, which set of snapshots must be destroyed to free up space.
  • There is work in progress to provide automatic and periodic disk scrubbing, in order to provide corruption detection and early disk-rotting detection. Currently the data scrubbing must be done manually with "zpool scrub" command.
  • Current ZFS compression/decompression code is very fast, but the compression ratio is not comparable to gzip or similar algorithms. The gzip compression algorithm was added in Solaris Nevada as part of 6536606 and is planned for a Solaris 10 update in Spring 2008.[19]
  • If a snapshot is taken or destroyed while the zpool is scrubbing/resilvering, the process will be restarted from the beginning.[20]
  • Not all symbolic links are protected by ditto blocks.[21][22]
  • Swapping over ZVOL pseudo-devices can hang the system.[23][24]
  • If a non-redundant disk in a zpool goes offline the entire operating system will panic on the next read or write. This can be a problem when for example a large server has multiple filesystems used for different purposes - one filesystem failure shouldn't cause the entire system to go down. This will be fixed when the zpool "failmode" option is added in Nevada b77[25][26]

2007 is a common year starting on Monday of the Gregorian calendar. ... 2007 is a common year starting on Monday of the Gregorian calendar. ...

Platforms

ZFS is part of Sun's own Solaris operating system and is thus available on both SPARC and x86-based systems. Since the code for ZFS is open source, a port to other operating systems and platforms can be produced without Sun's involvement. Sun UltraSPARC II Microprocessor Sun UltraSPARC T1 (Niagara 8 Core) SPARC (Scalable Processor Architecture) is a RISC microprocessor instruction set architecture originally designed in 1985 by Sun Microsystems. ... x86 or 80x86 is the generic name of a microprocessor architecture first developed and manufactured by Intel. ...


Nexenta OS

Nexenta OS, a complete GNU-based open source operating system built on top of the OpenSolaris kernel and runtime, includes a ZFS implementation, added in version alpha1. More recently, Nexenta Systems announced NexentaStor, their ZFS storage appliance providing NAS/SAN/iSCSI capabilities and based on Nexenta OS. NexentaStor includes a GUI that simplifies the process of utilizing ZFS. Also, Nexenta announced in February of 2008 a significant release, called version NexentaCore Platform 1.0, of their operating system which serves as a basis for software appliances from Nexenta and other distributions. Nexenta OS is a port of Debian to the OpenSolaris kernel. ... GNU (pronounced ) is a computer operating system composed entirely of free software. ... OpenSolaris is an open source project created by Sun Microsystems to build a developer community around Solaris Operating System technology. ... In computing, Nexenta OS is an Debian-based GNU/Solaris operating system. ...


Mac OS X

In a post on the opensolaris.org zfs-discuss mailing list, Apple Inc. announced it was porting ZFS to their Mac OS X operating system.[27] From Mac OS X 10.5 Developer Seed 9A321, support for ZFS has been included, but lacks the ability to act as a root partition, noted above. Also, attempts to format local drives using ZFS were unsuccessful; this is a known bug.[28] Apple Inc. ... Mac OS X (pronounced ) is a line of graphical operating systems developed, marketed, and sold by Apple Inc. ...


On June 6, 2007, Sun's CEO Jonathan I. Schwartz announced that Apple would make ZFS "the" filesystem in Mac OS 10.5 Leopard.[29] Marc Hamilton, VP for Solaris Marketing later wrote to clarify that, in his opinion, Apple is planning to use ZFS in future versions of Mac OS X, but not necessarily as the default filesystem for Mac OS X 10.5 Leopard.[30] In the release version of Mac OS X 10.5, ZFS is available in read-only mode from the command line, which lacks the possibility to create zpools or write to them,[31] but Apple has also released the "ZFS Read/Write Developer Preview 1.1 for Leopard"[32], which allows read-write access and the creation of zpools. The installer for the "ZFS Read/Write Developer Preview 1.1 for Leopard" is currently only working on version 10.5.0, and has not been updated for version 10.5.1 and above.[33] As of January 2008, Apple provides read-write binaries and source, but they must be installed by hand. is the 157th day of the year (158th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... Jonathan Schwartz speaking at the 2005 Web 2. ... Mac OS X version 10. ...


Linux

Porting ZFS to Linux is complicated by the fact that the GNU General Public License, which governs the Linux kernel, prohibits linking with code under certain licenses, such as CDDL, the license ZFS is released under.[34] One solution to this problem is to port ZFS to Linux's FUSE system so the filesystem runs in userspace instead. A project to do this was sponsored by Google's Summer of Code program in 2006, and is in Beta stage as of May 2007.[35] Running a file system outside the kernel on traditional Unix-like systems can have a significant performance impact. However, NTFS-3G (another file system driver built on FUSE) performs well when compared to other traditional file system drivers.[36] This shows that excellent performance is possible with ZFS on Linux after proper optimization. Sun Microsystems has stated that a Linux port is being investigated.[37] This article is about operating systems that use the Linux kernel. ... GPL redirects here. ... The Linux kernel is a Unix-like operating system kernel. ... In computing, software that is copyrighted and licensed under a software license is done so principally under two categories of licensing schemes. ... Common Development and Distribution License (CDDL) is an open source license, produced by Sun Microsystems, based the Mozilla Public License, version 1. ... Filesystem in Userspace (FUSE) is a Free (GPL and LGPLed) Unix kernel module that allows non-privileged users to create their own file systems without the need to write any kernel code. ... See Filing system for this term as it is used in libraries and offices In computing, a file system is a method for storing and organizing computer files and the data they contain to make it easy to find and access them. ... An operating system usually segregates the available system memory into kernel space and user space. ... The Google Summer of Code is an annual program, first held during the northern hemisphere summer of 2005, in which Google awards cash prizes to students who successfully complete a free software / open-source coding project during the summer. ... A context switch is the computing process of storing and restoring the state (context) of a CPU such that multiple processes can share a single CPU resource. ... NTFS-3G is an open source, freely available NTFS driver for Linux with read and write support. ...


BSD

Pawel Jakub Dawidek has ported and committed ZFS to FreeBSD for inclusion in FreeBSD 7.0, released on February 28, 2008.[38] FreeBSD is a Unix-like free operating system descended from AT&T UNIX via the Berkeley Software Distribution (BSD) branch through the 386BSD and 4. ...


As a part of the 2007 Google Summer of Code ZFS is being ported to NetBSD.[39] The Google Summer of Code is an annual program, first held during the northern hemisphere summer of 2005, in which Google awards cash prizes to students who successfully complete a free software / open-source coding project during the summer. ... NetBSD is a freely redistributable, open source version of the Unix-like BSD computer operating system. ...


Other

There are no plans to port ZFS to HP-UX or AIX.[37] HP-UX (Hewlett Packard UniX) is Hewlett-Packards proprietary implementation of the Unix operating system, based on System V (initially System III). ... AIX (Advanced Interactive eXecutive) is a proprietary operating system developed by IBM based on UNIX System V. Before the product was ever marketed, the acronym AIX originally stood for Advanced IBM UNIX. AIX has pioneered numerous network operating system enhancements, introducing new innovations later adopted by Unix-like operating systems...


Adaptive Endianness

Pools and their associated ZFS file systems can be moved between different platform architectures, including systems implementing different byte orders. The ZFS block pointer format stores filesystem metadata in an endian-adaptive way; individual metadata blocks are written with the native byte order of the system writing the block. When reading, if the stored endianness doesn't match the endianness of the system, the metadata is byte-swapped in memory. In computing, endianness is the byte (and sometimes bit) ordering in memory used to represent some kind of data. ...


This does not affect the stored data itself; as is usual in POSIX systems, files appear to applications as simple arrays of bytes, so applications creating and reading data remain responsible for doing so in a way independent of the underlying system's endianness. POSIX or Portable Operating System Interface[1] is the collective name of a family of related standards specified by the IEEE to define the application programming interface (API) for software compatible with variants of the Unix operating system. ...


See also

Free software Portal

Image File history File links Free_Software_Portal_Logo. ... The following lists identify, characterise and link to more thorough information on computer file systems. ... The following tables compare general and technical information for a number of file systems. ... The VERITAS File System, or VxFS, is an extent-based file system that was the first commercial journaling file system, and was developed by VERITAS Software. ... The Veritas Volume Manager, VVM or VxVM is a proprietary logical volume manager from Veritas. ... The Write Anywhere File Layout, or WAFL, is a file system designed by Network Appliance for use in their Network File System server appliances. ... Network Appliance, Inc. ... NILFS is a log-structured file system implementation for Linux. ... Nippon Telegraph and Telephone (日本電信電話 Nippon Denshin Denwa) is a telephone company that dominates the telecommunication market in Japan. ... LZJB is the name for the lossless data compression algorithm invented by Jeff Bonwick to compress crash dumps and data in ZFS. LZJB source code Categories: | ... A versioning file system is a file system which provides for the concurrent existence of several versions of a file. ...

References

  1. ^ a b OpenSolaris.org. Sun Microsystems. Retrieved on 2007-10-21.
  2. ^ a b ZFS: the last word in file systems. Sun Microsystems (September 14, 2004). Retrieved on 2006-04-30.
  3. ^ Jeff Bonwick (October 31, 2005). ZFS: The Last Word in Filesystems. Jeff Bonwick's Blog. Retrieved on 2006-04-30.
  4. ^ Sun Celebrates Successful One-Year Anniversary of OpenSolaris. Sun Microsystems (June 20, 2006).
  5. ^ Jeff Bonwick (2006-05-04). You say zeta, I say zetta. Jeff Bonwick's Blog. Retrieved on 2006-09-08.
  6. ^ Solaris ZFS Administration Guide. Sun Microsystems. Retrieved on 2007-10-02.
  7. ^ ZFS Best Practices Guide. Solaris Performance Wiki. Retrieved on 2007-10-02.
  8. ^ Solaris ZFS Administration Guide. Sun Microsystems. Retrieved on 2007-10-05.
  9. ^ Solaris ZFS Administration Guide. Sun Microsystems. Retrieved on 2007-10-05.
  10. ^ Jeff Bonwick (September 25, 2004). 128-bit storage: are you high?. Sun Microsystems. Retrieved on 2006-07-12.
  11. ^ Smokin' Mirrors. Jeff Bonwick's Weblog (2006-05-02). Retrieved on 2007-02-23.
  12. ^ ZFS Block Allocation. Jeff Bonwick's Weblog (2006-11-04). Retrieved on 2007-02-23.
  13. ^ Ditto Blocks - The Amazing Tape Repellent. Flippin' off bits Weblog (2006-05-12). Retrieved on 2007-03-01.
  14. ^ Architecture ZFS for Lustre. Sun Microsystems. Retrieved on 2008-02-18.
  15. ^ Latest ZFS add-ons. milek's blog (2007-03-28). Retrieved on 2007-03-29.
  16. ^ ZFS Bootable datasets - happily rumbling. Tim Foster's blog (2007-03-29). Retrieved on 2007-04-01.
  17. ^ The Dynamics of ZFS. Roch Bourbonnais' Weblog (2006-06-21). Retrieved on 2007-02-19.
  18. ^ Implementing fbarrier() on ZFS. zfs-discuss (2007-02-13). Retrieved on 2007-02-13.
  19. ^ zfs-discuss ZFS gzip compression. Prabahar Jeyaram (2007-09-29). Retrieved on 2007-12-11.
  20. ^ scrub/resilver has to start over when a snapshot is taken. OpenSolaris Bug Tracker (2005-10-30). Retrieved on 2007-03-14.
  21. ^ symlinks and ditto blocks. OpenSolaris Forums (2007-03-28). Retrieved on 2007-07-13.
  22. ^ zpl symlinks should have their own object type. OpenSolaris Bug Tracker (2007-01-23). Retrieved on 2007-07-13.
  23. ^ Plans for swapping to part of a pool. OpenSolaris Forums (2007-07-12). Retrieved on 2007-07-14.
  24. ^ system hang while zvol swap space shorted. OpenSolaris Bug Tracker (2007-02-26). Retrieved on 2007-07-14.
  25. ^ Panic when ZFS pool goes down?. OpenSolaris Forums (2002-02-25).
  26. ^ zpool failmode property [PSARC/2007/567 FastTrack timeout 10/08/2007] (2007-10-10).
  27. ^ Porting ZFS to OSX. zfs-discuss (April 27, 2006). Retrieved on 2006-04-30.
  28. ^ Mac OS X 10.5 9A326 Seeded. InsanelyMac Forums (December 14, 2006). Retrieved on 2006-12-14.
  29. ^ Sun announce ZFS is "the file system" in Mac OS X v10.5. Sun (June 6, 2007). Retrieved on 2007-06-06.
  30. ^ Marc Hamilton's weblog: Apple is planning to use the ZFS file system from OpenSolaris in future versions of their OS. Marc Hamilton's weblog (June 7, 2007). Retrieved on 2007-06-07.
  31. ^ Apple: Leopard offers limited ZFS read-only. MacNN (June 12, 2007). Retrieved on 2007-06-23.
  32. ^ Apple delivers ZFS Read/Write Developer Preview 1.1 for Leopard. Ars Technica (October 7, 2007). Retrieved on 2007-10-07.
  33. ^ Ché Kristo (November 18, 2007). ZFS Beta Seed v1.1 will not install on Leopard.1 (10.5.1) « ideas are free. Retrieved on 2007-12-30.
  34. ^ Jeremy Andrews (April 19, 2007). Linux: ZFS, Licenses and Patents. Retrieved on 2007-04-21.
  35. ^ Ricardo Correia (May 26, 2006). ZFS on FUSE/Linux. Retrieved on 2006-07-15.
  36. ^ Szabolcs Szakacsits (November 28, 2007). NTFS-3G Read/Write Driver Performance. Retrieved on 2008-01-20.
  37. ^ a b Fast Track to Solaris 10 Adoption: ZFS Technology. Solaris 10 Technical Knowledge Base. Sun Microsystems. Retrieved on 2006-04-24.
  38. ^ Dawidek, Pawel (April 6, 2007). ZFS committed to the FreeBSD base. Retrieved on 2007-04-06.
  39. ^ NetBSD Google Summer of Code projects: ZFS.

Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 294th day of the year (295th in leap years) in the Gregorian calendar. ... is the 257th day of the year (258th in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 120th day of the year (121st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 120th day of the year (121st in leap years) in the Gregorian calendar. ... is the 171st day of the year (172nd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 124th day of the year (125th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 251st day of the year (252nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 275th day of the year (276th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 275th day of the year (276th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... For other uses, see 5th October (Serbia). ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... For other uses, see 5th October (Serbia). ... is the 268th day of the year (269th in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 193rd day of the year (194th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 122nd day of the year (123rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 54th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 308th day of the year (309th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 54th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 132nd day of the year (133rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 60th day of the year (61st in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 49th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 87th day of the year (88th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 88th day of the year (89th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 88th day of the year (89th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 91st day of the year (92nd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 172nd day of the year (173rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... [[Media:Italic text]]{| style=float:right; |- | |- | |} is the 50th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 44th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 44th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 272nd day of the year (273rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 345th day of the year (346th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 303rd day of the year (304th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 73rd day of the year (74th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 87th day of the year (88th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 194th day of the year (195th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 23rd day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 194th day of the year (195th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 193rd day of the year (194th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 195th day of the year (196th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 57th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 195th day of the year (196th in leap years) in the Gregorian calendar. ... Also see: 2002 (number). ... is the 56th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 283rd day of the year (284th in leap years) in the Gregorian calendar. ... is the 117th day of the year (118th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 120th day of the year (121st in leap years) in the Gregorian calendar. ... is the 348th day of the year (349th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 348th day of the year (349th in leap years) in the Gregorian calendar. ... is the 157th day of the year (158th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 157th day of the year (158th in leap years) in the Gregorian calendar. ... is the 158th day of the year (159th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 158th day of the year (159th in leap years) in the Gregorian calendar. ... is the 163rd day of the year (164th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... is the 280th day of the year (281st in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 280th day of the year (281st in leap years) in the Gregorian calendar. ... is the 322nd day of the year (323rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ...