Bug 80735
| Summary: | software raid 5 sync causes incorrect load average | ||
|---|---|---|---|
| Product: | [Retired] Red Hat Linux | Reporter: | Steven Pritchard <steve> |
| Component: | kernel | Assignee: | Arjan van de Ven <arjanv> |
| Status: | CLOSED WONTFIX | QA Contact: | Brian Brock <bbrock> |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | 7.3 | ||
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | i686 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2004-09-30 15:40:21 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
After the resync finished, the load average dropped back to normal. Bug is still present in i686 kernel-2.4.20-20.9 on the same box.
# uptime
2:43pm up 1:11, 2 users, load average: 45.11, 42.69, 36.52
# cat /proc/mdstat
Personalities : [raid5]
read_ahead 1024 sectors
md0 : active raid5 sdg1[5] sdf1[4] sde1[3] sdd1[2] sdc1[1] sdb1[0]
244227520 blocks level 5, 64k chunk, algorithm 2 [6/6] [UUUUUU]
[===========>.........] resync = 55.1% (26955244/48845504) finish=56.2min
speed=6481K/sec
unused devices: <none>
# uname -a
Linux hostname 2.4.20-20.9 #1 Mon Aug 18 11:45:58 EDT 2003 i686 unknown
Adding dev.raid.speed_limit_max = 6000 to /etc/sysctl.conf "fixed" the problem on that system, so apparently swamping the SCSI bus was making the load spike insanely. I haven't needed to rebuild the RAID lately to see if recent Fedora kernels behave any differently. Thanks for the bug report. However, Red Hat no longer maintains this version of the product. Please upgrade to the latest version and open a new bug if the problem persists. The Fedora Legacy project (http://fedoralegacy.org/) maintains some older releases, and if you believe this bug is interesting to them, please report the problem in the bug tracker at: http://bugzilla.fedora.us/ |
From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.1) Gecko/20021003 Description of problem: On a single-processor 1GHz Celeron running kernel 2.4.18-18.7.x, while running raid5syncd on a 6-disk SCSI array (on an Adaptec 29160N), top reports the following: 10:45am up 1:34, 7 users, load average: 164.48, 164.36, 156.67 240 processes: 238 sleeping, 2 running, 0 zombie, 0 stopped CPU states: 23.8% user, 25.7% system, 0.0% nice, 50.4% idle Mem: 772644K av, 336508K used, 436136K free, 0K shrd, 26132K buff Swap: 2046736K av, 20K used, 2046716K free 71636K cached Note the inflated load average with only two processes running. (The system has been running at 75% idle, give or take, for the last hour.) /proc/mdstat: Personalities : [raid5] read_ahead 1024 sectors md0 : active raid5 sdg1[5] sdf1[4] sde1[3] sdd1[2] sdc1[1] sdb1[0] 244227520 blocks level 5, 64k chunk, algorithm 2 [6/6] [UUUUUU] [==========>..........] resync = 53.0% (25909532/48845504) finish=60.3min speed=6330K/sec unused devices: <none> The system is totally responsive, although the high load average makes some daemons (such as sendmail) stop accepting connections. Version-Release number of selected component (if applicable): How reproducible: Didn't try Additional info: