Re: [Help] How to use "iostat" or other command to monitor Software RAID I/O ????
On Thu, 10 Jul 2003 11:18, axacheng wrote:
> Hello lists :
> Does anyone knows , How to monitor Software RAID disk I/O ????
> i have a Software RAID5 device named "/dev/md0" , i've tried to use
> "iostat" to monitor /dev/md0 I/O status ...
/proc/partitions does not have any counts for software RAID, so you can't
monitor the RAID itself. It does have counts for the block devices that
comprise a software RAID so it would not be THAT difficult to write an iostat
type program that can read /proc/mdstat to determine which devices comprise a
software RAID and then monitors their stats in /proc/partitions and uses some
addition to determine the total for the software RAID device.
The CPU overhead of incrementing counters is negligible, there's no reason why
the counts for software RAID could not be displayed in /proc/partitions, I
think that this is a minor bug in the software RAID code.
If someone posts a patch to fix it to the linux-kernel list then it should
have some chance of being accepted.
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