On Monday 20 August 2007, martin f krafft wrote: > also sprach Mike Bird <[EMAIL PROTECTED]> [2007.08.20.1627 +0200]: > > > 3) RAID 5 is not resilient against multiple failures. We now use > > > RAID 1. RAID 1 is also faster, although it sometimes requires > > > more drives. In extreme cases we use RAID 1 with three or more > > > drives. > > > > On Monday 20 August 2007 00:36, martin f krafft wrote: > > > RAID 1 is also not resilient to multiple failures. > > > > Is the loss of N-1 members of an N-way RAID-1 not survivable? > > Well, yes. I see what you mean now. You can survive N-1 harddrives > failing at once while with RAID5, that better not happen before > a spare could take over.
In this case, I had 4 drives, so if one failed, then the spare should have been added but that hadn't happened. I've also tested the two "failed" drives and they are quite functional. A friend made a point to me that could make a difference. I had not partitioned the drives since mdadm seems okay without partitions. He said even if I only use one drive-wide partition, I should still partition the drives in a RAID first. Fortunately, this was in a backup system so I can get new drives and rebuild it from scratch with the larger drives. I've already got ideas for using the "failed" drives that are proving to be just fine. Hal