[BlueOnyx:07920] Re: Software RAID rebuild faster

[Christoph Schneeberger]

Generally said, make sure that only little or even better no writes and
reads happen during sync (shutdown daemons and processes if you can
afford it).
Most probably the underlying hardware speed is your bottleneck, but you
can play with the following 2 parameters to see if you can speed up the
syncing a bit (they do what you actually tried with renicing):

/proc/sys/dev/raid/speed_limit_max
/proc/sys/dev/raid/speed_limit_min

In most cases they are set as 200000 and 1000 respectively. Upping the
max won't help much, but upping the min value can speed things quite a bit.

HTHTH*,
Christoph

* HopeThisHelpsTheHoping


Richard Morgan wrote:
> Hi, hope someone can help...
>  
> I have to go to the data centre tomorrow (a two hour drive each
> way) to swap a failed disk - my tests and experience make me
> think that the RAID1 rebuild will take about five hours for the 1TB
> disks.  As I also want to replace the current good disk with a new one
> it means waiting for the rebuild to complete.
>  
> Is there anyway to speed this up?  I've experimented with 'top' then
> 'r' for renice - changing it to -15 or -20, etc.  It doesn't make much
> difference.  I was wondering if there was anything else I could do
> even if the server is offline for a while.
>  
> Here's hoping :o), Richard