How to find the device in a RAID1 under Linux?

Question

besides:

head -2 /dev/dm-16 | strings | grep ^id

how can I find that which device belongs to a given MD RAID1 array?

score 1 · Answer 1 · answered Aug 20 '13 at 18:44

1

Try this command:

cat /proc/mdstat

answered Aug 20 '13 at 18:44

Shimi

doesn't shows which was the pair of the device that is in the RAID1 md. – gasko peter Aug 20 '13 at 18:58
md1 : active raid1 sdb2[1] sda2[0] =>
sdb2, sda2 ? isn't that what you're referring to by "pair"? – Shimi Aug 20 '13 at 19:15
it only shows 1 sdXX device :) I'm searching for it's pair – gasko peter Aug 20 '13 at 19:17
sdb2, sda2, are two devices. no? – Shimi Aug 20 '13 at 19:18

score 1 · Answer 2 · answered Aug 20 '13 at 18:48

1

How about

mdadm -D /dev/mdX

replacing X by your actual RAID-1 device number.

answered Aug 20 '13 at 18:48

Joseph R.

doesn't shows which was the pair of the device that is in the RAID1 md. – gasko peter Aug 20 '13 at 19:09
@gaskopeter It's been a while since I managed a RAID array. Can you please tell me what the output of mdadm -D /dev/mdX show on your box? and what you expected it to show? – Joseph R. Aug 20 '13 at 19:10

score 0 · Accepted Answer · answered Aug 20 '13 at 19:57

0

since RAID1 means there are two identical disks, so checksums need to match

[root@SERVER ~]# head -100 /dev/sdb3|cksum
2207220453 6836
[root@SERVER ~]# head -100 /dev/sda3|cksum
2207220453 6836
[root@SERVER ~]#

answered Aug 20 '13 at 19:57

gasko peter

hope it's a really good answer for every situation... metadata/etc could differ?? – gasko peter Aug 26 '13 at 07:50

score 0 · Answer 4 · answered Aug 20 '13 at 22:00

0

blkid(8) should be informative.

answered Aug 20 '13 at 22:00

D McKeon

4 Answers4