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Using the Kilo-Client storage grid
When a test engineer requests time on the Kilo-Client grid, the engineering support team assigns the engineer a single Kilo-Client node booted from a LUN clone of the Golden LUN. The engineer then installs applications and tools on the SAN booted OS required for his testing needs.
If the customized SAN booted OS needs to be used on more than one node, the customized boot LUN gets cloned again using LUN clone technology. The LUN clone is then split from the original LUN, unmapped from any blades to preserve the original LUN, and optionally archived to a NetApp NearStore system for future use. In cases where the customized boot LUN is significant enough, it could be used as a new Golden LUN. To use the customized LUN on additional Kilo-Client nodes, a snapshot copy of the FlexVol volume containing the new OS SAN boot LUN is created; writable LUN clones are created for as many blades as the engineer wants for testing.
By using LUN clones, the thinly provisioned boot LUNs allow each bootable LUN clone to be unique and writable, and yet share blocks from the original LUN. "It isn't uncommon that hundreds of LUN clones get created from a single original LUN," says Klem.
|Advantages of a SAN boot architecture|
Rapid client provisioning and repurposing. By separating a
server and the boot medium, a server can be assigned to a different boot volume by remapping it from one boot LUN to another. Various boot LUNs are identified by assigned world wide port name (WWPN) for Fibre Channel and an iSCSI qualified name (IQN) for iSCSI.
Scalable and flexible. SAN booting enables scaling horizontally by simply adding servers or server blades and boot images on the back-end storage. Moreover, servers can be mapped easily from one boot LUN to another one by remapping the boot LUN assignment.
RAID protection for boot images. Because the boot LUNs reside on enterprise storage, they inherently have the RAID protection of the array. Boot LUNs eliminate having a pair of mirrored disks in each server.
Boot images can be spread across multiple spindles. Performance can be adjusted up or down, depending on the number of spindles assigned to the boot images. Local boot disks are typically limited to a pair of mirrored drives.
Inherent backups. Because the boot LUNs reside on enterprise storage, they're automatically backed up as part of the array backup, eliminating the need to back up each individual server.
This was first published in October 2007