Op 2013-03-27 om 13:12 schreef Paul Mather: > On Mar 26, 2013, at 11:44 PM, Bill Arlofski 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. >
Thanks for the advice on RAID configuration. Now we can go back to > >> 24TB internal storage (8x 3TB disks) and use virtual tapes. so (cheap) disks as alternative to backup tapes. Groeten Stappers ------------------------------------------------------------------------------ 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