Les Stott wrote: > David Nalley wrote: >> Hi Matthew, >> >> I don't think the concern is so much that a client computer's drive and one >> of >> your backuppc box's drive would fail at the same instant, but rather what >> the cost of one drive in the backuppc box's drive would be. >> Loosing a single drive if you pool them all together with LVM means you >> loose >> the entire logical volume, which means you have to start all backups over >> again from scratch. That's too much of a waste of resources to me >> (particularly if you are using rsync.) but that is just my perspective, it >> may be perfectly acceptable in your environment, and is a decision you have >> to make. >> >> If you go the RAID 1 option, I'd create two RAID 1 arrays and LVM them >> together, or perhaps look at the RAID 10/0+1 option and put all 4 drives in >> the same array. I still think that I would use LVM since it gives you some >> flexibility in the future. Red Hat's new LVM guide is pretty decent, gives >> lots of real world examples, you may want to check it out as well. >> >> > a better raid and redundancy option is to software mirror a raid 5 > volume over the 4 disks. That yields 1.4tb of storage. if you lose 1 > drive the array still functions fine, you remove the faulty disk and > replace it and rebuild, no data loss. > > as pointed out above using just lvm across all 4 drives means if one > disk fails the lvm crashes, data loss occurs. > > if you do 2 raid 1 mirrors you only get 1tb total storage. I'm not a big > fan of extending lvm's across different physical disks, even if they are > mirrored. > > You can still have lvm under the raid 5 array (make the raid array type > physical volume) if you want, but it depends on your needs and it boils > down to 2 questions: 1. do you want to easily resize partitions and > create new ones in the 1.4tb raid array? and 2. do you want to do any > sort of live snapshot backups? > if you answer yes to either question, use lvm, if no to both then just > do the software raid. > > > Regards, > > Les >
Hello Les, thanks for the response. Since this will be for BackupPC, all of the data pool has to be on one volume. If I ever did run out of space, having LVM could be a temporary life saver. From what I've read, it can't hurt any to use LVM. Your case for RAID 5 is very convincing. I think that I may change to that with LVM layered on top. If something goes wrong with one of my disks, how will I know? And more importantly, how will I know which one to replace (the disks are all physically identical). thanks again for your time. -Matthew ------------------------------------------------------------------------- SF.Net email is sponsored by: The Future of Linux Business White Paper from Novell. From the desktop to the data center, Linux is going mainstream. Let it simplify your IT future. http://altfarm.mediaplex.com/ad/ck/8857-50307-18918-4 _______________________________________________ BackupPC-users mailing list BackupPC-users@lists.sourceforge.net List: https://lists.sourceforge.net/lists/listinfo/backuppc-users Wiki: http://backuppc.wiki.sourceforge.net Project: http://backuppc.sourceforge.net/
