On 04/12/11 6:02 AM, Marian Marinov wrote: > > Yes... but with such RAID10 solution you get only half of the disk space... so > from 10 2TB drives you get only 10TB instead of 16TB with RAID6. those disks are $100 each. whats your data worth? The rebuild time goes way up as the number of drives in the raid stripe goes up. in this case, the OP is talking about a 40TB array, so thats a TWENTY TWO drive raid. NOONE I know in the storage business will use larger than a 8 or 10 drive raid set. If you really need such a massive volume, you stripe several smaller raidsets, so the raid6 version would be 2 x 12 x 2TB or 24 drives for raid6+0 == 40TB. but the OP's application is backup. for backup, it really doesn't matter what the volume size is, more smaller file systems is fine, so you can partition your backups by date interval or whatever. let me throw out another thing. I assume this 40TB backup server is not just ONE backup of the current state, but an archive of point-in-time backups? you better have more than one of them, where you backup the backup on the 2nd. there's any number of scenarios the raid6 won't protect against, including file system corruption, raid controller failure where it dumps across a whole stripe, etc.