On Mar 26, 2013, at 11:44 PM, Bill Arlofski <waa-bac...@revpol.com> wrote:
> On 03/26/13 22:33, Wood Peter wrote: >> Hi, >> >> I'm planning to use Bacula to do file level backup of about 15 Linux >> systems. Total backup size is about 2TB. >> >> For Bacula server I'm thinking to buy Dell PE R520 with 24TB internal >> storage (8x 3TB disks) and use virtual tapes. > > Hi Peter. First, you're going to want some RAID level on that server and > RAID0 is not (IMHO) RAID at all. :) > > At a minimum you're going to want to set up (for example) RAID5 in the server > which will give you a maximum of 7 x 3 = 21 TB since the equivalent of 1 full > drive is used for parity, spread across all of the drives in a RAID5 array. > > Having said that, RAID5 does not have the best write speeds, but other RAID > levels that will give more redundancy and better write speeds will use > significantly more drives and give you less total storage. You may need to > spend some time to consider your redundancy and read/write throughput > requirements. > > Also, you will generally want to configure at least one drive as a hot spare > so the RAID controller can automatically and immediately fail over to it in > the case of a drive failure in the array. > > So that takes away at least 3 more TB, so now your down to 18TB total storage > with a minimally configured RAID5 array with 1 hot spare. > > Just some things to consider. :) Another thing to consider is that with large capacity drives (3 TB) combined into large RAID-5 arrays there is an increased likelihood of a catastrophic array failure during an array rebuild due to an initial drive failure. For this reason, RAID-6 would be preferred for such large arrays. Reliability of large RAID arrays is one of the motivations behind raidz3 (triple-parity redundancy) in ZFS. See, e.g., http://queue.acm.org/detail.cfm?id=1670144 for details. Cheers, Paul. ------------------------------------------------------------------------------ Own the Future-Intel® Level Up Game Demo Contest 2013 Rise to greatness in Intel's independent game demo contest. Compete for recognition, cash, and the chance to get your game on Steam. $5K grand prize plus 10 genre and skill prizes. Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
