Spare disk periodically woken up

Spare disk periodically woken up

[Jan Ceuleers]

Hi there.

I'm very sorry if this is an FAQ; I've searched the wiki but have not 
been able to find the answer.

I have five disks, four of which form a RAID5 set, with the fifth being 
a spare. This fifth disk is normally spun down, or at least it should 
be. (It's a bit more complicated than that, as is evident from the info 
included below, but this is essentially it).

I recently noticed that this fifth disk is periodically spun up for 
reasons unknown. It's not due to SMART monitoring because I've disabled 
the SMART daemon altogether.

My /proc/mdstat is shown below; the disk that is periodically spun up is 
/dev/sdf.

How can I find out what is causing my standby disk to spin up?

Many thanks.

Cheers, Jan

========= /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] 
[raid4] [raid10]
md2 : active raid5 sdf2[4](S) sda2[0] sdd2[3] sdc2[2] sdb2[1]
       934765824 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU]

md1 : active raid1 sdb1[0] sdd1[1]
       979840 blocks [2/2] [UU]

md0 : active raid1 sdf1[2](S) sda1[0] sdc1[1]
       979840 blocks [2/2] [UU]

unused devices: <none>

Re: Spare disk periodically woken up

[David Lethe]

Is interval regular, like exactly every X minutes?

-----Original Message-----

From:  "Jan Ceuleers" <jan.ceuleers@computer.org>
Subj:  Spare disk periodically woken up
Date:  Wed Jan 28, 2009 2:01 pm
Size:  1K
To:  "linux-raid@vger.kernel.org" <linux-raid@vger.kernel.org>

Hi there. 
 
I'm very sorry if this is an FAQ; I've searched the wiki but have not  
been able to find the answer. 
 
I have five disks, four of which form a RAID5 set, with the fifth being  
a spare. This fifth disk is normally spun down, or at least it should  
be. (It's a bit more complicated than that, as is evident from the info  
included below, but this is essentially it). 
 
I recently noticed that this fifth disk is periodically spun up for  
reasons unknown. It's not due to SMART monitoring because I've disabled  
the SMART daemon altogether. 
 
My /proc/mdstat is shown below; the disk that is periodically spun up is  
/dev/sdf. 
 
How can I find out what is causing my standby disk to spin up? 
 
Many thanks. 
 
Cheers, Jan 
 
========= /proc/mdstat 
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5]  
[raid4] [raid10] 
md2 : active raid5 sdf2[4](S) sda2[0] sdd2[3] sdc2[2] sdb2[1] 
       934765824 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU] 
 
md1 : active raid1 sdb1[0] sdd1[1] 
       979840 blocks [2/2] [UU] 
 
md0 : active raid1 sdf1[2](S) sda1[0] sdc1[1] 
       979840 blocks [2/2] [UU] 
 
unused devices: <none> 
 
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