Check actual resync times:
> cat /var/log/messages.8 | synctime array, blocks, sec, blocks/s, start, finish md10, 2104448, 63, 33403.9, Mar 16 23:33:37, Mar 16 23:34:40 md11, 2096384, 64, 32756.0, Mar 16 23:35:30, Mar 16 23:36:34 md13, 2096384, 127, 16507.0, Mar 16 23:36:34, Mar 16 23:37:37 md12, 2096384, 191, 10975.8, Mar 16 23:37:37, Mar 16 23:38:41 md12, 2104448, 61, 34499.1, Mar 16 23:50:38, Mar 16 23:51:39 md5, 2096384, 63, 33275.9, Mar 16 23:51:50, Mar 16 23:52:53 md12, 2104448, 61, 34499.1, Mar 17 00:00:39, Mar 17 00:01:40 md6, 2104384, 122, 17249.0, Mar 17 00:01:40, Mar 17 00:02:41 md5, 2104384, 183, 11499.4, Mar 17 00:02:41, Mar 17 00:03:42 md7, 6289344, 366, 17184.0, Mar 17 00:03:42, Mar 17 00:06:45 md9, 52170944, 1873, 27854.2, Mar 17 00:06:45, Mar 17 00:31:52 md8, 52187008, 3489, 14957.6, Mar 17 00:31:52, Mar 17 00:58:48
> cat ~/bin/synctime | cksum 1035800810 528 > cat ~/bin/synctime #!/bin/awk -f #GNU Awk 3.1.1 #Copyright (C) 1989, 1991-2002 Free Software Foundation. #md resync time csv
BEGIN{
printf "array, blocks, sec, blocks/s, start, finish\n"
}/md: syncing RAID array/{
sdate = $1 " " $2 " " $3
"date -d \"" sdate "\" +%s" | getline start
dev = $10
}
/md: using.*window,/{
size = $14
}
/md:.*sync done\./{
fdate = $1 " " $2 " " $3
"date -d \"" fdate "\" +%s" | getline finish
delta = finish-start
printf "%4s, %10s, %5s, %6.1f, %s, %s\n",
dev,size,delta,size/delta,sdate,fdate
}
#endGuy wrote:
-----Original Message----- From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid- owner@xxxxxxxxxxxxxxx] On Behalf Of Nils-Henner Krueger Sent: Wednesday, March 30, 2005 4:13 AM To: linux-raid@xxxxxxxxxxxxxxx Subject: syncing RAID1 with more than 10MB/sec
Syncing a raid1 takes long time for large disks because of the 10MB/sec limit:
Mar 30 10:58:31 imap1 kernel: raid1: raid set md2 not clean; reconstructing mirrors Mar 30 10:58:31 imap1 kernel: raid1: raid set md2 active with 2 out of 2 mirrors Mar 30 10:58:31 imap1 kernel: md: syncing RAID array md2 Mar 30 10:58:31 imap1 kernel: md: minimum _guaranteed_ reconstruction speed: 100 KB/sec/disc. Mar 30 10:58:31 imap1 kernel: md: using maximum available idle IO bandwith (but not more than 10000 KB/sec) for reconstruction.
Is it possible to raise this value (without recompiling)? I know about possible performance tradeoffs with other processes, I'm just generally interested.
Thanks.
nils-henner
Yes. For details: man md
The default of 10,000 has been increased to 100,000 in newer kernels. I don't know which kernels.
If you want to override the defaults you could add these 3 lines to /etc/sysctl.conf: # RAID rebuild min/max speed K/Sec per device dev.raid.speed_limit_min = 1000 dev.raid.speed_limit_max = 100000
Adjust above as required. The above will take effect after a reboot.
To see current values type these 2 lines: cat /proc/sys/dev/raid/speed_limit_min cat /proc/sys/dev/raid/speed_limit_max
To temporarily change the defaults use these 2 commands: echo 1000 > /proc/sys/dev/raid/speed_limit_min echo 100000 > /proc/sys/dev/raid/speed_limit_max
Adjust above as required. The above will take effect now.
Guy
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