PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME CPU COMMAND
7775 root 15 0 1344 1344 916 S 0.2 0.0 0:02 0 top
14220 root 15 0 1216 1216 920 R 0.2 0.0 0:00 1 top -c
I have a server with two cPanel accounts, each running gallery2. Load has been high:
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Sar output (done at a less busy time):
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Hardware: 1 Intel 2.4 GHz 1066FSB - Conroe Xeon 3060 (Dual Core) 2 Generic 1024 MB DDR2 667 ECC 1 Maxtor 250GB SATA 7200RPM MaxLine Plus II 1 Unknown Onboard SATA 1 Dell Single socket 1067FSB - Quad Core Capable PowerEdge 840
Howmuch %iowait is too much?
Since it's using less than 1GB Swap, there's enough RAM?
How do I get more specific than httpd as the cause of the load. The gallery script is the only thing running so is the execution time of PHP the bottleneck? If PHP and apache are single threaded would a quad core reduce load? Does lighttpd run PHP faster?
I was wondering if anyone has had luck with 3ware 9650's in a RAID 10 to help bring down iowait?
I currently have a VPS node that see's spikes in iowait and i'd like to bring it down. I've been considering getting a 9650 in a JBOD setup (so then I don't need to reinstall the whole node) with a battery backup to enable the cache.
My two questions are:
- In JBOD, does the write cache enable at all? - Would the write cache help bring down the iowait much?
Drive wise we have 4 x 500GB drives in a raid10 (soft for now).
iowait creates high performance degradation. There was no changes in server software & configuration. Sometimes server work very slow, count of apache processes is high - there is no any processes and scripts who can use a lot of hdd resources.
Sites located on customer server does not create high load, and not subjected to any attacks.
I received response from DC:
I did some research for this and it seems that other people has experienced similar issues and is reporting that it is a kernel bug have you ran yum update to receive the latest kernel if not you can try and update and see if that may resolve your issue.
CENTOS 5.2 Cpanel / WHM Linux *** 2.6.18-92.1.22.el5PAE #1 SMP Tue Dec 16 12:36:25 EST 2008 i686 i686 i386 GNU/Linux
I try to run "yum update kernel" but it seems installed kernel is up to date.
[mysqlhotcopy] interactive-timeout Whenever there are a lot of members online on my forum, the iowait shoot up, >30% and often times hovering at 60%. It'll eventually drop down to normal levels. However, during the high iowait, there are over 2.5GB of free memory according to the command, free -m
is it due to mysql not optimized or other processes? I don't think the bottleneck is on the cpu or ram.
I am running in a High load problem lately. I have one of those cheap 1and1 servers which was running fine until 2 weeks ago. Once I rebooted accidentaly, it did not come back with some unrepairable kernel errors and I had to re-image it.
I chose to reimage the server with CentOS 5, for better support. The new re-image worked fine for some days, at least so I thought and now I am having high loads. The server crashes if not monitored every moment as the load is unpredictable.
Just a restart of the Apache will bring the server back to normality, but I am not sure if it is apache or some other script to be blamed. I have beeing monitoring through apache server-status, but I cannot organize something unusual in the high load moments.
12:00:29 AM CPU %user %nice %system %iowait %steal %idle 12:10:01 AM all 9.14 0.00 5.52 44.66 0.00 40.68 12:20:14 AM all 6.83 0.00 3.98 27.88 0.00 61.32 12:30:10 AM all 6.44 0.00 4.20 81.25 0.00 8.11 12:40:09 AM all 5.25 0.00 4.09 81.93 0.00 8.73 12:50:15 AM all 5.11 0.00 3.79 90.74 0.00 0.36 01:00:07 AM all 7.22 0.00 4.52 57.11 0.00 31.15 01:10:13 AM all 6.89 0.00 4.01 55.38 0.00 33.71 01:20:14 AM all 4.37 0.00 3.27 41.88 0.00 50.48 01:30:25 AM all 4.26 0.00 3.29 63.42 0.00 29.03 01:40:06 AM all 27.18 0.00 4.75 58.27 0.00 9.80 01:50:03 AM all 29.64 0.00 6.61 51.50 0.00 12.25 02:00:07 AM all 27.00 0.00 8.48 55.49 0.00 9.03 02:10:10 AM all 19.29 0.00 4.97 73.80 0.00 1.94 02:20:04 AM all 37.85 0.00 6.78 40.70 0.00 14.67 02:30:05 AM all 15.65 0.00 4.80 68.47 0.00 11.08 02:40:08 AM all 9.06 0.00 5.60 37.49 0.00 47.86 02:50:07 AM all 5.36 0.00 3.62 42.29 0.00 48.73 03:00:02 AM all 6.05 0.00 4.08 47.27 0.00 42.60 03:10:02 AM all 4.22 0.00 3.68 38.17 0.00 53.93 03:20:02 AM all 4.06 0.00 3.75 41.37 0.00 50.82 03:30:22 AM all 4.42 0.00 3.93 45.25 0.00 46.41 03:40:11 AM all 4.34 0.00 3.95 39.58 0.00 52.13 03:50:02 AM all 4.67 0.00 4.01 32.53 0.00 58.80 04:00:08 AM all 3.72 0.00 3.87 28.40 0.00 64.02 04:10:02 AM all 13.49 0.00 6.58 20.82 0.00 59.10 04:20:01 AM all 6.70 0.00 4.63 6.06 0.00 82.61 04:30:02 AM all 1.44 0.00 1.21 4.75 0.00 92.59 04:40:01 AM all 12.42 0.00 8.12 7.65 0.00 71.81 04:50:02 AM all 1.43 0.00 1.07 4.02 0.00 93.47 05:00:02 AM all 1.60 0.00 1.40 8.62 0.00 88.38 05:10:10 AM all 3.80 0.00 3.02 17.86 0.00 75.32 05:20:06 AM all 5.10 0.00 4.22 23.34 0.00 67.34 05:30:02 AM all 1.54 0.00 1.40 11.22 0.00 85.85 05:40:05 AM all 1.75 0.00 1.89 13.12 0.00 83.23 05:50:12 AM all 2.15 0.00 2.22 18.92 0.00 76.72 06:00:02 AM all 1.92 0.00 2.01 12.87 0.00 83.20 06:10:02 AM all 2.27 0.00 2.16 11.53 0.00 84.04 06:20:03 AM all 3.56 0.00 3.02 25.26 0.00 68.16 06:30:10 AM all 2.66 0.00 2.05 18.13 0.00 77.16 06:40:02 AM all 2.58 0.00 2.25 22.87 0.00 72.30 06:50:02 AM all 2.68 0.00 1.92 15.77 0.00 79.63 07:00:03 AM all 3.06 0.00 2.48 26.01 0.00 68.46 07:10:03 AM all 3.65 0.00 3.20 36.54 0.00 56.61
07:10:03 AM CPU %user %nice %system %iowait %steal %idle 07:20:03 AM all 4.40 0.00 3.28 43.86 0.00 48.46 07:30:02 AM all 4.10 0.00 3.17 31.30 0.00 61.43 07:40:06 AM all 7.67 0.00 3.95 50.79 0.00 37.59 07:50:02 AM all 4.72 0.00 3.11 44.30 0.00 47.86 08:00:03 AM all 5.57 0.00 3.72 47.15 0.00 43.56 08:10:07 AM all 10.66 0.00 3.59 71.62 0.00 14.13 08:20:17 AM all 5.67 0.00 3.42 58.81 0.00 32.10 08:30:10 AM all 11.12 0.00 3.49 76.71 0.00 8.67 08:40:03 AM all 7.00 0.00 3.36 47.94 0.00 41.71 Average: all 7.53 0.00 3.76 38.90 0.00 49.81 Some configurations: The reimage partittioning looks like this:
processor : 1 vendor_id : GenuineIntel cpu family : 15 model : 3 model name : Intel(R) Pentium(R) 4 CPU 2.80GHz stepping : 4 cpu MHz : 2793.324 cache size : 1024 KB
