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