[linux-lvm] Re: RAID 1 on Device Mapper - best practices?

Micah Anderson micah at riseup.net
Fri Nov 21 13:02:05 UTC 2003

The md code decided it was going to resync the mirror
> at between 100KB/sec and 100000KB/sec. The actual rate was 100KB/sec,
> while the device was otherwise idle. By increasing
> /proc/.../speed_limit_min, I was able to crank the resync rate up to
> 20MB/sec, which is slightly more reasonable but still short of the
> ~60MB/sec this RAID is capable of.

On Thu, 20 Nov 2003, M?ns Rullg?rd wrote:

> > Sure, it might suck the living daylights out of system performance,
> It does.

Doesn't have to... With 2.2 kernels, you can simply use 'cat
/proc/sys/dev/md/speed-limit', to see the *minimum* rebuild rate. You
can change it using something like:
'echo 200000 > /proc/sys/dev/md/speed-limit'.

With 2.4 kernels, there are two files in '/proc/sys/dev/raid/', called
'speed_limit_max' and 'speed_limit_min'. I think the rest is pretty
obvious. You don't have to destroy system performance...


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