CentOS - Feb 2005 - RAID 1 sync

Is my new 300GB RAID 1 array REALLY going to take 18936 minutes to
sync!!???

is this hardware or software RAID..also what hardware do you have 
this running on?

Nigel Kendrick wrote:
> Is my new 300GB RAID 1 array REALLY going to take 18936 minutes to
> sync!!???
> 
> 
> _______________________________________________
> CentOS mailing list
> CentOS at caosity.org
> http://lists.caosity.org/mailman/listinfo/centos
> .
> 
-- 
My "Foundation" verse:
Isa 54:17  No weapon that is formed against thee shall prosper; 
and every tongue that shall rise against thee in judgment thou 
shalt condemn. This is the heritage of the servants of the LORD, 
and their righteousness is of me, saith the LORD.

-- carpe ductum -- "Grab the tape"
CDTT (Certified Duct Tape Technician)

Linux user #322099
Machines:
206822
256638
276825
http://counter.li.org/

On Thu, 3 Feb 2005, Nigel Kendrick wrote:
> Is my new 300GB RAID 1 array REALLY going to take 18936 minutes to
> sync!!???
Hi Nigel,

If SW-RAID (i.e. raidtools / mdadm) :-

You can tune kernel parameters to increase max/min speed values here:

# cat /proc/sys/dev/raid/speed_limit_max
10000
# cat /proc/sys/dev/raid/speed_limit_min
100

Set this to, say, power of 10 (or more):

# sysctl -w dev.raid.speed_limit_max=100000
# sysctl -w dev.raid.speed_limit_min=1000

Additionally tweak it further up with:

# renice -20 `pidof mdrecoveryd`


Do all this _before_ you glue up the mirror.


# dmesg
<...>
md: minimum _guaranteed_ reconstruction speed: 1000 KB/sec/disc.
md: using maximum available idle IO bandwith (but not more than 100000
KB/sec) for reconstruction.
<...>

# cat /proc/mdstat
<...>
md8 : active raid1 sdb5[2] sda5[0]
      2096384 blocks [2/1] [U_]
      [========>............]  recovery = 43.2% (907584/2096384)
finish=0.3min speed=50421K/sec
<...>


Don't recommend this if your server is I/O intensive and in production
use. Massive performance degration while reconstructing.


SW-RAID rules. :-)


Regards,
 Morten


-- 
morten t?rmoen, morten at basefarm.no, +47 97 77 47 77
basefarm as, http://www.basefarm.no, +47 40 00 41 00