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ATA over Ethernet (AoE) is a network protocol developed by the Brantley Coile Company[1], designed for accessing ATA storage devices over Ethernet networks. It gives the possibility to build SANs with low-cost, standard technologies. In networking, a communications protocol or network protocol is the specification of a set of rules for a particular type of communication. ...
ATA cables: 40 wire ribbon cable top, 80 wire ribbon cable bottom Advanced Technology Attachment (ATA) is a standard interface for connecting storage devices such as hard disks and CD-ROM drives inside personal computers. ...
Ethernet is a large, diverse family of frame-based computer networking technologies that operates at many speeds for local area networks (LANs). ...
In computing, a storage area network (SAN) is an architecture to attach remote computer storage devices such as disk array controllers, tape libraries and CD arrays to servers in such a way that to the operating system the devices appear as locally attached devices. ...
AoE does not rely on network layers above Ethernet, such as IP, UDP, TCP, etc. This means that AoE is not routable over LANs and is intended for SANs only. An alternative to iSCSI, the AoE specification is 8 pages compared with iSCSI's 257 pages. Ethernet is a large, diverse family of frame-based computer networking technologies that operates at many speeds for local area networks (LANs). ...
The Internet Protocol (IP) is a data-oriented protocol used for communicating data across a packet-switched internetwork. ...
User Datagram Protocol (UDP) is one of the core protocols of the Internet protocol suite. ...
The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite, often simply referred to as TCP/IP. Using TCP, applications on networked hosts can create connections to one another, over which they can exchange streams of data using Stream Sockets. ...
LOCAL AREA NETWORK Local area network scheme A local area network is a computer network covering a small geographic area, like a home, office, or group of buildings. ...
Internet SCSI (iSCSI) is a network protocol standard, officially ratified on 2003-02-11 by the Internet Engineering Task Force, that allows the use of the SCSI protocol over TCP/IP networks. ...
Operating system support
The following OS provides native ATA over Ethernet support: It has been suggested that Maintenance OS be merged into this article or section. ...
This article does not cite any references or sources. ...
Ethernet is a large, diverse family of frame-based computer networking technologies that operates at many speeds for local area networks (LANs). ...
Coraid [3] provided the original device drivers for FreeBSD, and current versions are maintained by Stacey D. Son[4]. Linux (IPA pronunciation: ) is a Unix-like computer operating system. ...
Coraid, Inc. ...
Windows XP loading drivers during a Safe Mode bootup A device driver, or a software driver is a specific type of computer software, typically developed to allow interaction with hardware devices. ...
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. ...
AoE support is currently being beta tested for the Solaris operating system, SPARC and x86. Solaris is a computer operating system developed by Sun Microsystems. ...
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. ...
An Intel Pentium 4 chip; early Northwood build x86 or 80x86 is the generic name of a microprocessor architecture, first developed and manufactured by Intel. ...
A European based storage company, Rocket Division Software has added AoE support into their StarPort Storage Controller[5] for Windows, which is an iSCSI and AoE Initiator, RAM disk and Virtual DVD drive.
2DegreesFrost [6], a Bellingham, WA software company has shipped a driver for Mac OS X (10.4) providing AoE support.
Hardware support The Coraid [7] company offers an ATA over Ethernet hard disk called EtherDrive. Coraid, Inc. ...
ATA cables: 40 wire ribbon cable top, 80 wire ribbon cable bottom Advanced Technology Attachment (ATA) is a standard interface for connecting storage devices such as hard disks and CD-ROM drives inside personal computers. ...
Ethernet is a large, diverse family of frame-based computer networking technologies that operates at many speeds for local area networks (LANs). ...
Typical hard drives of the mid-1990s. ...
Also the vblade program makes it possible to export hard disks using inexpensive computers running Linux. Two independent implementations of vblade exist: A userspace one (part of aoetools package) and another one implemented as a linux kernel module.
Related Concepts Although AoE is a simple network protocol, it opens up a complex realm of storage possibilities. To understand and evaluate these storage scenarios, it helps to be familiar with a few concepts.
Block Storage The ATA in "ATA over Ethernet" is a kind of wire protocol for disk drives. Data is written to the disk and read back from it in one or more fixed-size chunks of data called blocks. ATA cables: 40 wire ribbon cable top, 80 wire ribbon cable bottom Advanced Technology Attachment (ATA) is a standard interface for connecting storage devices such as hard disks and CD-ROM drives inside personal computers. ...
Disk Drive is the afternoon show on CBC Radio Two. ...
In computing (specifically data transmission and data storage), block size indicates a nominal size, usually expressed in bytes or bits, of a block of data. ...
The ATA over Ethernet protocol simply puts ATA commands into low-level network packets, so that an Ethernet network effectively replaces the cable that goes to the disk drive. Just as blocks of data can go to a disk drive through a ribbon cable in a computer, they can also go over ethernet cables. Ethernet is a large, diverse family of frame-based computer networking technologies that operates at many speeds for local area networks (LANs). ...
ATA cables: 40 wire ribbon cable top, 80 wire ribbon cable bottom Advanced Technology Attachment (ATA) is a standard interface for connecting storage devices such as hard disks and CD-ROM drives inside personal computers. ...
A packet is the fundamental unit of information carriage in all modern computer networks. ...
Ethernet is a large, diverse family of frame-based computer networking technologies that operates at many speeds for local area networks (LANs). ...
Left: 20-way grey ribbon cable with wire no. ...
Cat 6 - Category - 6, (ANSI/TIA/EIA-568-B.2-1) A cable standard for Gigabit Ethernet and other interconnect that is backward compatible with Category 5 cable, Cat-5e and Cat-3. ...
The ribbon cable doesn't care what is inside of the blocks of data, and neither does AoE. You can read and write any blocks of data you want, but most of the time, a file system is used to organize the data. It has been suggested that Crash counting be merged into this article or section. ...
Filesystems on block storage Traditionally, a filesystem has been used on a computer that is the sole user of its hard disk. Filesystems like ext3, XFS, HFS+, and NTFS were designed with this assumption in mind. The ext3 or third extended filesystem is a journalled file system that is commonly used by the Linux operating system. ...
XFS is a high-performance journaling file system created by Silicon Graphics for their IRIX operating system. ...
HFS Plus or HFS+ is a file system developed by Apple Computer to replace their Hierarchical File System (HFS) as the primary file system used on Macintosh computers. ...
NTFS (New Technology File System) is the standard file system of Windows NT, including its later versions Windows 2000, Windows XP, Windows Server 2003, and Windows Vista. ...
When you use AoE, using an Ethernet network in the place of a cable, it's possible to violate that assumption. For traditional filesystems, that is a dangerous thing to do, leading to filesystem corruption or kernel panics. Ethernet is a large, diverse family of frame-based computer networking technologies that operates at many speeds for local area networks (LANs). ...
The Mac OS X kernel panic alert Kernel panic on a Linux 2. ...
Cluster filesystems avoid the assumption that only one computer has access to the block device. They are designed to allow multiple members of a cluster of computers to use a shared block device safely, by coordinating their actions. 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. ...
Examples of cluster filesystems are GFS and OCFS2. Global File System (or GFS) is a shared-storage journaled cluster, or distributed file system. ...
OCFS stands for Oracle Cluster File System. ...
SANs (Storage Area Networks) File Systems are another means to avoid this problem. MetaSAN is a SAN software package that supports AoE. It is produced by a European software company, Tiger Technology Sarl [8]. In computing, a storage area network (SAN) is an architecture to attach remote computer storage devices such as disk array controllers, tape libraries and CD arrays to servers in such a way that to the operating system the devices appear as locally attached devices. ...
MetaSAN is Tiger Technologys high-performance cross-platform Storage Area Network (SAN) management software. ...
Disk Drives The AoE target is a hard disk, or something that appears to be a hard disk. A few key points regarding hard disks are: Typical hard drives of the mid-1990s. ...
- Access speed is dependent upon disk RPM (rotational latency), head movement speed (seek time), magnetic density, accuracy of head alignment on the track, data location on disk, and interface electronics;
- Random disk access speed is entirely dominated by seek time;
- Random access is over 100 times slower than sequential access[9];
- Single disk sequential access is typically 50-80 MB/s;
- RAID generally improves sequential and random access performance;
- Host OS and disk filesystem try to store data sequentially to help the disk perform (McKusick 1984).
Fast, cheap, good: choose two” In computing, a redundant array of independent disks (more commonly known as a RAID) is a system of using multiple hard drives for sharing or replicating data among the drives. ...
Ethernet The wikipedia article on Ethernet networks has more information, but for AoE it is helpful to keep in mind the points listed below. Ethernet is a large, diverse family of frame-based computer networking technologies that operates at many speeds for local area networks (LANs). ...
In computer networking a Media Access Control address (MAC address) or hardware address or adapter address is a quasi-unique identifier attached to most network adapters (NICs). ...
Ethernet is a large, diverse family of frame-based computer networking technologies that operates at many speeds for local area networks (LANs). ...
Ethernet is a large, diverse family of frame-based computer networking technologies that operates at many speeds for local area networks (LANs). ...
Ethernet Flow Control is defined by IEEE 802. ...
Retransmission refers to one of the basic mechanisms used by protocols operating over a packet switched computer network to provide reliable communication (such as that provided by a reliable byte stream, for example TCP). ...
Ethernet is a large, diverse family of frame-based computer networking technologies that operates at many speeds for local area networks (LANs). ...
A cyclic redundancy check (CRC) is a type of function that takes as input a data stream of any length and produces as output a value of a certain fixed size. ...
Network Storage When using an Ethernet network to access block storage, there are several potential advantages: Ethernet is a large, diverse family of frame-based computer networking technologies that operates at many speeds for local area networks (LANs). ...
- It is easier to add storage capacity.
- The amount of storage is practically unlimited.
- Access can be controlled by creating ad hoc ethernet networks.
- Common commodity hardware can be used.
- Data backup may be easier.
- Data may be shared instead of being confined to one computer.
In information technology, backup refers to the copying of data so that these additional copies may be restored after a data loss event. ...
Config String The AoE protocol provides a mechanism for host-based cooperative locking. When more than one AoE initiator is using an AoE target, they must cooperate. The hosts need a way to avoid interfering with one another as they use and modify the data on the shared AoE device.
The hosts can simply communicate, using, for example, TCP/IP to send messages to one another. Through communication, the hosts can agree which host has the right to access particular blocks on the shared storage. The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite, often simply referred to as TCP/IP. Using TCP, applications on networked hosts can create connections to one another, over which they can exchange streams of data using Stream Sockets. ...
Another option is to use the storage device itself as the mechanism for determining the access of particular hosts. The AoE protocol includes a "config string" feature. If more than one host tries to set the config string, only one actually succeeds. The other host receives an error. At that point, the "winner" is decided and the winner can proceed to establish an access policy.
See also In computer science, HyperSCSI is a network protocol for sending and receiving SCSI commands. ...
Internet SCSI (iSCSI) is a network protocol standard, officially ratified on 2003-02-11 by the Internet Engineering Task Force, that allows the use of the SCSI protocol over TCP/IP networks. ...
External links - Articles:
- ATA Over Ethernet: Putting Hard Drives on the LAN — Linux Journal (28 April 2005)
- ATA-over-Ethernet enables low-cost Linux-oriented SAN — LinuxDevices.com (23 June 2004)
- The ATA over Ethernet (AoE) Protocol — Linux Magazine (June 15th, 2005)
- Protocol:
- AoE protocol description (PDF file)
- AoE protocol specification
- Emulator and Tools:
- Live CD:
Linux Journal is a monthly magazine published by SpecializedSystemsConsultants (SSC) of Seattle, first published in March 1994. ...
Linux Magazin (ISSN 1432-640X) is a German professional journal. ...
The Portable Document Format (PDF) is the file format created by Adobe Systems, in 1993, for document exchange. ...
References - Hitachi (12 September 2006), Hard Drive Specification Deskstar 7K500, Hitachi.
- Marshall Kirk McKusick, William N. Joy, Samuel J. Leffler and Robert S. Fabry. A Fast File System for UNIX. Technical Report Computer Systems Research Group, Computer Science Division, Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley, CA 94720.
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