[CentOS] 40TB File System Recommendations

Tue Apr 12 18:51:45 UTC 2011
John R Pierce <pierce at hogranch.com>

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.