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Thread: Tracking down load issue
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05-13-2008, 09:07 PM #1Web Hosting Master
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Tracking down load issue
Hi,
I have a CentOS box here that is causing some strange load. Brand new X3230 (4*2.66Ghz), 2GB ram and 2*500GB SATA2 in raid-1 on a LSI MegaIDE controller.
Basically the server is continuesly at a load of 1. However I dont see why. No CPU load, and no IO as far as I can see. Does anybody have a tip where to look for the problem?
top - 05:01:56 up 1:53, 2 users, load average: 1.00, 1.02, 1.20
Tasks: 81 total, 1 running, 80 sleeping, 0 stopped, 0 zombie
Cpu0 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu1 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu2 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu3 : 0.3%us, 0.0%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 2072132k total, 591072k used, 1481060k free, 65652k buffers
Swap: 2048276k total, 0k used, 2048276k free, 461532k cached# iostat
Linux 2.6.18-53.el5 (xxxx.xandrios.net) 05/14/2008
avg-cpu: %user %nice %system %iowait %steal %idle
2.65 0.56 5.56 0.97 0.00 90.26
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 6.44 99.67 255.89 686581 1762792# hdparm -tT /dev/sda
/dev/sda:
Timing cached reads: 16092 MB in 2.00 seconds = 8057.39 MB/sec
Timing buffered disk reads: 88 MB in 3.04 seconds = 28.92 MB/sec
Only thing I could think of is that it has something to do with the raidcard. The data transfer rate is quite low. Could it be that the card is rebuilding the array? Can I check that without rebooting?Last edited by Xandrios; 05-13-2008 at 09:12 PM.
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05-13-2008, 09:19 PM #2Eternal Member
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You should be able to check the state of the array (no reboot required) by downloading the CLI and/or storage manager from your RAID card manufacturer.
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05-13-2008, 09:21 PM #3WHT Addict
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Load average refers to how many processes are using or waiting for the CPU, hence it is possible a single process can cause a load of 1 without using much CPU. I'm not sure under what circumstances this might occur but it is possible.
Don't most RAID controllers require that you use the BIOS to rebuild a a RAID set?
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05-13-2008, 09:54 PM #4Web Hosting Master
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Thanks. I guess I should contact support to figure out which card it is exactly since dmesg does not seem to give a model no.
Load average refers to how many processes are using or waiting for the CPU, hence it is possible a single process can cause a load of 1 without using much CPU. I'm not sure under what circumstances this might occur but it is possible.
Don't most RAID controllers require that you use the BIOS to rebuild a a RAID set?Powered by Level3, GBLX and AT&T
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05-14-2008, 01:09 PM #5Web Hosting Master
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Turns out it is an onboard raidcontroller provided by the mainboard (Intel SR1530). They checked the HDD utilization and the drives were almost completely idle...so its not like there is a rebuild in progress or anything like that.
Besides IO, what could cause such load? It is *exactly* 1.0:
13:08:50 up 10:49, 2 users, load average: 1.00, 1.00, 1.00Powered by Level3, GBLX and AT&T
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05-14-2008, 01:20 PM #6Web Hosting Guru
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While running top, if you hit 'i' to filter out all of the idle processes, are you left with any processes in the list that are constantly in the "run" state?
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05-14-2008, 08:10 PM #7WHT Addict
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05-14-2008, 08:27 PM #8Retired Moderator
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* Moved to Tech/Security Issues.
Alex
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05-15-2008, 07:06 AM #9Web Hosting Master
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top - 06:57:39 up 1 day, 4:38, 1 user, load average: 1.00, 1.00, 1.00
Tasks: 138 total, 1 running, 137 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 2072132k total, 1188276k used, 883856k free, 122448k buffers
Swap: 2048276k total, 56k used, 2048220k free, 925808k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
423 root 15 0 0 0 0 D 0 0.0 0:00.00 megaide
14063 root 15 0 2172 1028 792 R 0 0.0 0:00.02 topPowered by Level3, GBLX and AT&T