SAN backups (3 posts)

Just posted in the virtualisation forum about high availability using Xen .. it reminded me about a virtual machine that I have running with a hosting provider. They have two VMware ESX heads in HA with an iSCSI SAN backend. Sounds decent ... except that the SAN controller died. Nothing lost but it was down for a few hours (not including the compulsory fsck when my virtual machine rebooted).

I'm sure there could have been a more reliable configuration, but what I'm wondering is, how do you keep your SAN backed up? (Not just VMs, but whatever other data you have on there.) No matter how reliable a system is you still have to allow for the possibility that you'll lose everything someday I guess.

a mirror SAN perhaps?

SAN Backup

They 'should' have HA iSCSI controllers that allow seamless failover if a failure occurs there.

A mirror is usually only used for complete DR and is not a backup. Some kind of logical corruption at the application or OS level will be manifested in the mirror.

A snapshot is an online backup that can be reverted to in the case of above. If you use NetApp, you get both on the mirror (full update copy and historical snapshots).

See http://media.netapp.com/documents/ar-0730.pdf