XserveRAID backups to SAN (possibly XSAN) connected tape fail. (4046245)

XserveRAID backups to SAN (possibly XSAN) connected tape fail.

Backups of XserveRAID data to a SAN attached drive/library will fail if the connection between the host and the RAID unit and the connection between the host and the drive/library are not physically or logically separated.

When attempting to run a File System backup of data located on an XserveRAID volume, to a tape drive located in the same SAN without physical or logical separation of the paths to host, the backup will fail. The tape used for the backup is then marked as Read Only. Backups of local data to the tape drive are successful. Likewise backups of XserveRAID data to a VTL created on local disk are successful.

This problem is the result of two FC interface paths (cables) connecting the host through the FC switch to the tape drives and library without a method to manage the two communications paths. This results in the host not having a consistent path for tape communications. Apple supports multipathing in the FC Host Adapter and XserveRAID, and often this is the default setting after installation. However, today across the industry FC sequential tape drives do not support multi path FC integrations.

Connections must be logically or physically separated to ensure a consistent communication path. The attached document details various solution options according to hardware setup. This document communicates the results of an interoperability test between NetVault, Apple, Qlogic FC switch, and Exabyte tape. The theory remains the same irrespective of which switch or tape drive/library is used.

SOL79654_Apple+IAR+081305_0

BakBone SFDC Solution Number: 00001249