Talk:Two Node Fedora 13 Cluster - Xen-Based Virtual Machine Host on DRBD+CLVM: Difference between revisions
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ARRAY /dev/md3 metadata=1.2 name=localhost.localdomain:3 UUID=b4fc7771:bef0b6a5:c4c40550:ab3bff42 | ARRAY /dev/md3 metadata=1.2 name=localhost.localdomain:3 UUID=b4fc7771:bef0b6a5:c4c40550:ab3bff42 | ||
</source> | </source> | ||
--[[User:SRSullivan|SRSullivan]] 20:05, 15 October 2010 (UTC) | |||
Revision as of 20:05, 15 October 2010
We'll remove the yum -y before the document goes live. For now, I want it there to save time while (repeatedly) rebuilding the clusters as it saves a lot of time.
--Digimer 18:58, 13 October 2010 (UTC)
Dealing with Raid 5/6
Under raid 5/6 if you follow these instruction to closely you'll end up with bad config data in mdadm.conf
cat /proc/mdstat
Personalities : [raid1] [raid6] [raid5] [raid4]
md3 : active raid5 sdd5[4] sdc5[2] sdb5[1] sda5[0]
1395170304 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [UUU_]
[=====>...............] recovery = 26.5% (123522028/465056768) finish=126.7min speed=44896K/sec
md2 : active raid5 sda1[0] sdd1[4] sdc1[2] sdb1[1]
62909952 blocks super 1.1 level 5, 512k chunk, algorithm 2 [4/4] [UUUU]
bitmap: 0/1 pages [0KB], 65536KB chunk
md1 : active raid5 sda2[0] sdd2[4] sdc2[2] sdb2[1]
6286848 blocks super 1.1 level 5, 512k chunk, algorithm 2 [4/4] [UUUU]
md0 : active raid1 sda3[0] sdd3[3] sdc3[2] sdb3[1]
255988 blocks super 1.0 [4/4] [UUUU]
unused devices: <none>
You will notice the [UUU_]. The default, and this is not in the documentation for mdadm, is to build the array with a degraded spare and then resync it. This is faster, but produces false data for the next step if it is done before the array completes it resync.
Ref: [1]
mdadm --detail --scan | grep md3 >> /etc/mdadm.conf
cat /etc/mdadm.conf
Will produce:
ARRAY /dev/md3 metadata=1.2 spares=1 name=localhost.localdomain:3 UUID=b4fc7771:bef0b6a5:c4c40550:ab3bff42
Which should actually be the following (with out the spares=1)
ARRAY /dev/md3 metadata=1.2 name=localhost.localdomain:3 UUID=b4fc7771:bef0b6a5:c4c40550:ab3bff42
--SRSullivan 20:05, 15 October 2010 (UTC)