How is RAID0 data recovered?

I agree Nichols.., however RAID 0 groups can be used for non-critical data needing high speed (particularly write speed) and low cost capacity in situations where the time to rebuild will not affect business processes. Information on RAID 0 groups should be already backed up or replicated in protected storage. RAID 0 offers no level of redundancy. Proactive hot sparing is not enabled for RAID 0 groups. A single drive failure in a RAID 0 group will result in complete data loss of the group. An unrecoverable media failure can result in a partial data loss. A possible use of RAID 0 groups is scratch drives or temp storage. Hence it is not recommend using RAID 0 for data with any business value

Regards,

Suman Pinnamaneni

Don’t think of a RAID 0 as a RAID. There are no parity or mirrored drives in RAID 0.

backups are not critical ?

Thanks Suman.  It's all cleared now. I initially thought that any type of disks are being replaced by hot spare in case it becomes faulty.  I've just learned that the RAID0 disks on our system are being used as backup volume hence it is non-critical.

if will blow your backup application mind if it loses data from cache before it has been written to the next long term storage,  very important not to lose this area either.

I assume he means backup dump volumes, which are later swept by a backup application. In that case, the loss of the LUN merely causes loss of the most recent dump file, or prevents a backup from completing. The primary application and the backups that have been swept into the backup application are still available.

If the LUN is truly used for long term storage of backups, then RAID5/6 would be advisable of course.

Richard J Anderson

Example I was thinking of would be a SQL server backup up to a dump file, then a separate backup application (Netbackup, Commvault, etc) coming in later and backing up that dump file.

A case can be made in that scenario is that if the RG fails, the LUN goes offline and either the SQL server dump job will fail with an error that the target is unavailable, or the backup job will simply fail.

If the LUN is actually being used as managed backup capacity for the backup application (ie: Netbackup Storage Pool, or Commvault Magnetic Library), then yes, losing that disk will cause all sorts of issues.

Richard J Anderson

wait until you need to restore something. You'll find out just how non critical a backup is