Visit Jeremy's Blog.
Go Back > Forums > Linux Forums > Linux - Software
User Name
Linux - Software This forum is for Software issues.
Having a problem installing a new program? Want to know which application is best for the job? Post your question in this forum.


  Search this Thread
Old 07-18-2009, 02:00 PM   #1
Registered: Dec 2007
Distribution: Debain Fluxbox
Posts: 76

Rep: Reputation: 15
AoE RAID5 slow build speed


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
Registered: Dec 2007
Distribution: Debain Fluxbox
Posts: 76

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.


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
extremly slow random read on new raid5 array Tomasu Linux - Server 1 05-30-2009 02:47 PM
Very slow raid5 resync alex6666 Linux - Hardware 3 12-12-2008 08:27 AM
Slow Speed??? ajeetraina Linux - Newbie 8 05-21-2008 01:18 AM
Speed from PC to PC very slow ddales Linux - Wireless Networking 0 02-22-2007 06:32 AM
NIC transfer speed fast... receive speed slow landev Linux - Networking 5 11-07-2006 03:09 PM > Forums > Linux Forums > Linux - Software

All times are GMT -5. The time now is 04:11 AM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration