Hey all, I'm new to linux RAID, sorry if these are duplicates, but I think I've found a couple bugs:
In the raidtab man page, the lines for nr-spare-disks are incorrect:
" nr-spare-disks count
Number of spare devices in the array; there should
be count spare-disk entries later in the file.
Spare disks may only be used with RAID4 and RAID5,
and allow the kernel to automatically build new
RAID disks as needed. "
Spare disks do work with RAID1.
----
The second thing I found is a little stranger:
I've made 4 partitions into a raid 1 array, 2 main and 2 spare. My raidtab is:
raiddev /dev/md0
raid-level 1
nr-raid-disks 2
nr-spare-disks 2
chunk-size 4
persistent-superblock 1
device /dev/hdd1
raid-disk 0
device /dev/hdd2
raid-disk 1
device /dev/hdd3
spare-disk 0
device /dev/hdd4
spare-disk 1
(I'm using partitions on the same hd for testing purposes)
I've been starting the array, mounting it and playing around with failures - simulating failures by mkfs'ing an unmounted partition. When the raid-disk 1 fails it falls over to one of the spares just as it's supposed to. When raid-disk 0 fails, mdstart reports the following "invalid argument /dev/md0" If I reverse the raid-disk numbers so that disk 0 is good and disk 1 is corrupted everything works fine. Example:
with the raidtab as above:
mkraid /dev/md0 ; mkfs /dev/md0; mount /dev/md0 /raid_test
copy some contents into /raid_test
umount /dev/mdo; raidstop /dev/md0
From here, if I mkfs /dev/hdd2 (corrupt the partition in raid-disk 1) and
startraid /dev/md0 it rebuilds the array with one of the spare disks
However, if I mkfs /dev/hdd1 (corrupt raid-disk 0) and startraid it responds with the above error. Switching raid-disk 0 and 1 in the raidtab allows startraid to function and the array is rebuilt on a spare.
Hope I've made this clear... I've got some free time to work with this if it is a problem (and I haven't done something incredibly stupid)...
Mike Y
--
"I don't need child-resistant caps on my medicine bottles. They say,
"Well, someone with children might come and visit you." Forget'em! Let 'em
take their chances. Anyone who visits me is accepting a certain level of
risk in the first place."
--George Carlin
myehle at wanadoo dot fr
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