Re: poor performance with raid1 / raid0

[Farkas Levente <lfarkas@bnap.hu>]

Paul Clements wrote:
> Per Andreas Buer wrote:
> 
>>Andrew Rechenberg <arechenberg@shermfin.com> writes:
>>
>>
>>>Check /proc/sys/dev/raid/speed_limit_[min|max].  If they are set too low
>>>then your re-mirror will behave as such.  To change just echo a new
>>>value:
>>>
>>>echo 30000 > /proc/sys/dev/raid/speed_limit_min
>>>echo 50000 > /proc/sys/dev/raid/speed_limit_max
>>>
>>
>>I did so - and now:
>>
>>md6 : active raid1 md16[2] sdd6[0]
>>      117185984 blocks [2/1] [U_]
>>      [>....................]  recovery =  0.1% (229120/117185984)
>>finish=59.5min speed=32731K/sec
> 
> 
> That's probably because you just lowered the values. The maximum is
> normally 100000. To check what the default values are, reboot and do:
> 
> cat /proc/sys/dev/raid/speed_limit_*
> 
> Then echo a _larger_ number into those files.
> 
> There is no absolute maximum value (except maybe 2^32), so don't be
> afraid to raise the values to 10 or 100 times what they were. That
> should ensure that your resync speed is close to its theoretical
> maximum.

can someone tell me what these numbers means?
of course my goal (as everyones) to achieve the maximum possible 
performance.
can I do any harm if I set these numbers to high?
it no, why not set it bu default?

thanks in advance.

-- 
   Levente                               "Si vis pacem para bellum!"