RAID Notation Examples

As the new Network RAID Notation Standard (SAM RAID Notation) is a bit complex, I felt that it would be useful to provide a list of common use scenarios and specific implementation examples and how they would be notated.

  • Scenario: Netgear ReadyNAS Pro 2 with XRAID mirror.  Notation: R1
  • Scenario: Two Netgear ReadyNAS Ultra units with local RAID 1 sync’d over the network using rsync.  Notation: R1{1}
  • Scenario: Two Drobo B800fs NAS devices each loaded with single parity RAID sync’d using DroboSync. Notation: R5{1}
  • Scenario: Two Drobo B800fs NAS devices each with dual parity RAID sync’d using DroboSync.  Notation: R6{1}
  • Scenario: Two Linux servers with R6 locally using DRBD Mode A or B (asynchronous.)  Notation: R6[1]
  • Scenario: Two Linux servers with R5 locally using DRBD Mode C (synchronous.)  Notation: R6(1)
  • Scenario: Three node VMware vSphere VSA cluster with local R10.  Notation: R10(1)3
  • Scenario: Windows server with two four disk R0 stripes mirrored.  Notation: 8R01
  • Scenario: Two FreeBSD servers with R10 using HAST with memsync.  Notation: R10[1]
  • Scenario: Two FreeBSD servers with R1 using HAST with sync.  Notation: R1(1)
  • Scenario: Two Windows file servers with R10 using Robocopy to synchronize file systems. Notation: R10{1}
  • Scenario: Single Netgear SC101 SAN* using ZSAN drivers on Windows with two disks. Notation: R(1)

Technology References:

HAST: http://wiki.freebsd.org/HAST

DRBD: http://www.drbd.org/users-guide/s-replication-protocols.html

DroboSync: http://www.drobo.com/solutions/for-business/drobo-sync.php

Rsync: http://rsync.samba.org/

Robocopy: http://technet.microsoft.com/en-us/library/cc733145%28v=ws.10%29.aspx

Notes:

*The Netgear SC101 SAN is interesting in that while it can hold two PATA drives internally and exposes them to the network as block devices, via the ZSAN protocol, through a single Ethernet interface but there is no internal communications between the devices so all mirroring of the array happens in Windows which actually sees each disk as an entirely separate SAN device each with its own IP address.  Windows has no way to know that the two devices are related. The RAID 1 mirroring is handled one hundred percent in software RAID on Windows and the SAN itself is always two independent PATA drives exposed raw to the network.  A very odd, but enlightening device.

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