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Old 07-18-2009, 02:00 PM   #1
poonippi
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Registered: Dec 2007
Distribution: Debain Fluxbox
Posts: 72

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AoE RAID5 slow build speed


Hi,

I've got 4 computers configured in an AoE cluster. On one of the 4 machines I'm configuring the exported partitions as a RAID5 device. Technically everything is working, but the RAID build speed is horrendously slow, I've been used to 40-50M/s:-

earth:~# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 etherd/e2.0[4] etherd/e1.0[2] etherd/e0.1[1] hda4[0]
102558528 blocks level 5, 64k chunk, algorithm 2 [4/3] [UUU_]
[=====>...............] recovery = 25.2% (8628732/34186176) finish=223.1min speed=1907K/sec

unused devices: <none>


I've checked DMA is enabled on each of the machines, and cranked up /proc/sys/dev/raid/speed_limit_min to 5MB, still no increase in speed.

Any ideas?
 
Old 07-23-2009, 02:38 PM   #2
poonippi
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Registered: Dec 2007
Distribution: Debain Fluxbox
Posts: 72

Original Poster
Rep: Reputation: 15
Added an addition AoE partition, and grew the RAID5 device. The build speed is now proportionately less. Without calculating anything, I'll assume adding additional disks will slow RAID5 build speed:-

earth:~$ cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 etherd/e3.0[4] hda4[0] etherd/e2.0[3] etherd/e1.0[2] etherd/e0.1[1]
102558528 blocks super 0.91 level 5, 64k chunk, algorithm 2 [5/5] [UUUUU]
[>....................] reshape = 0.8% (307444/34186176) finish=552.5min speed=1021K/sec

unused devices: <none>

Last edited by poonippi; 07-23-2009 at 04:24 PM.
 
  


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