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Obsolete Releases => SME Server 7.x => Topic started by: mrrickus on January 20, 2011, 10:01:00 AM

Title: Confused over cat /proc/mdstat results
Post by: mrrickus on January 20, 2011, 10:01:00 AM: Hi - first post and a bit of a novice i'm affraid!
I'm trying to establish if my RAID1 is working or not.
Running 7.5.1 and these are the results from cat /proc/mdstat and fdisk -l.
I just don't know how to read them!
Can anyone please help demystify this for me? Many thanks!

Code: [Select]
[root@ppr-server-bristol ~]# cat /proc/mdstat Personalities : [raid1] md2 : active raid1 sdb2[0] sda2[1] 976655488 blocks [2/2] [UU] md1 : active raid1 sdb1[0] sda1[1] 104320 blocks [2/2] [UU] unused devices: <none> [root@ppr-server-bristol ~]# fdisk -l Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sda1 * 1 13 104384+ fd Linux raid autodetect Partition 1 does not end on cylinder boundary. /dev/sda2 13 121601 976655647 fd Linux raid autodetect Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdb1 * 1 13 104391 fd Linux raid autodetect /dev/sdb2 14 121601 976655610 fd Linux raid autodetect Disk /dev/sdd: 1000.2 GB, 1000202043392 bytes 255 heads, 63 sectors/track, 121600 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdd1 * 1 121601 976758784 7 HPFS/NTFS Disk /dev/md1: 106 MB, 106823680 bytes 2 heads, 4 sectors/track, 26080 cylinders Units = cylinders of 8 * 512 = 4096 bytes Disk /dev/md1 doesn't contain a valid partition table Disk /dev/md2: 1000.0 GB, 1000095219712 bytes 2 heads, 4 sectors/track, 244163872 cylinders Units = cylinders of 8 * 512 = 4096 bytes Disk /dev/md2 doesn't contain a valid partition table Disk /dev/dm-0: 999.0 GB, 999049658368 bytes 2 heads, 4 sectors/track, 243908608 cylinders Units = cylinders of 8 * 512 = 4096 bytes Disk /dev/dm-0 doesn't contain a valid partition table Disk /dev/dm-1: 1040 MB, 1040187392 bytes 2 heads, 4 sectors/track, 253952 cylinders Units = cylinders of 8 * 512 = 4096 bytes Disk /dev/dm-1 doesn't contain a valid partition table [root@ppr-server-bristol ~]#
Title: Re: Confused over cat /proc/mdstat results
Post by: byte on January 20, 2011, 01:40:55 PM: Quote from: mrrickus on January 20, 2011, 10:01:00 AM
Hi - first post and a bit of a novice i'm affraid!

Hi and welcome :)

Quote
Can anyone please help demystify this for me? Many thanks!

mdstat is the one you want to look at for any raid checks/issues, also check this link out:

http://tldp.org/FAQ/Linux-RAID-FAQ/x37.html#failrecover

fdisk is more of a partitioning tool which you really never use as the install takes care of all.

Try using google and type mdstat you will see literally hundreds of results and always remember google is your friend :) type the command or question and it 99.9% of the time you will find what your looking for.

Hope this helps.
Title: Re: Confused over cat /proc/mdstat results
Post by: mrrickus on January 20, 2011, 02:22:20 PM: Thanks Byte!

The link was very helpful - learning slowly!!
I've been googling around this, but haven't found any good info explaining the "blocks" element of the mdstsat result.
It looks to me like the raid IS working from what I've read, but I'm concerned about the massive difference in block size on md2 (976655488 blocks [2/2] [UU]) & md1 (104320 blocks [2/2] [UU]).
I hate to ask for answers - but do you know if this means I have a problem (brain function excluded!).
Back to google now.
Title: Re: Confused over cat /proc/mdstat results
Post by: CharlieBrady on January 20, 2011, 02:44:57 PM: Quote from: mrrickus on January 20, 2011, 02:22:20 PM
It looks to me like the raid IS working from what I've read, but I'm concerned about the massive difference in block size on md2 (976655488 blocks [2/2] [UU]) & md1 (104320 blocks [2/2] [UU]).

All SME systems have one small RAID1 device to contain /boot and one larger one containing everything else.

Quote
I hate to ask for answers - but do you know if this means I have a problem (brain function excluded!).

If you have a problem, and email will be sent to the admin mailbox.
Title: Re: Confused over cat /proc/mdstat results
Post by: mrrickus on January 20, 2011, 03:15:20 PM: Ah ha,
Good info thanks - not got any errors in mail, so I'll assume the RAID is working properly.
Thanks folks!
Title: Re: Confused over cat /proc/mdstat results
Post by: Jáder on January 20, 2011, 04:54:05 PM: You can watch the result of mdstat and search for this: [UU]

Two "U" is a good thing.... just one of them a bad news if you have TWO HDDs (same apply to more than 2 HDDs I presume!).