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View Full Version : Thoughts on server load


dandanfirema
07-13-2002, 07:21 PM
I was just thinking about all the focus that we and our customers put on server load. I have a server that I have been monitoring for load issues.

Server specs: 1G Celeron
512M Ram
IDE 7200RPM drive


Serverload ranges 1-5 from time to time. Server CPU never peaks and hardly ever runs over 80%...usually in the 20% range. Swap is always lest than 60-80M used.

Server houses almost exclusively php/cgi sites. Very little of the server is actually used for static pages.

Server gets moderate traffic. One of the forums peaks around 40 simultaneous users.

Understanding that server load is the average number of requests waiting to be completed.

If, for example, one of my forum pages gets a request that requires 34 separate mysql queries to build the page before the page is gzipped and sent to the customer. Wouldn't this inherently create processes that are waiting to complete?

I have yet to observe the server, even when load was 3+ experience any poor performace serving pages.

Any thoughts?

RRolfe
07-13-2002, 08:50 PM
i am not exactly sure what your looking for here but the 34mysql query's would create extra processes that are waiting to be completed.

maybe adding more ram and taking it to 1gb would help lower the load on the server?

dandanfirema
07-13-2002, 08:52 PM
Thank you for replying whw. That is actually what I am planning to do. I guess what I am getting at is this....

Does the way that these webpages....mostly forums....inherently create load on the server?

Tazzman
07-13-2002, 09:09 PM
Well, I had some heavy server load due to heavy mySQL usages. Popped in a load of extra ram bringing it to 1 GIG and server load dropped to between 0.10 and 0.20. Just prooves ram is good :D

RRolfe
07-13-2002, 09:09 PM
well of course a bunch of mysql queries are going to create a server load.... if you really want to find out what process's are taking up the most cpu time (in realtime stats)

run the command "top"

dandanfirema
07-13-2002, 09:14 PM
Thats sort of the quandry here....the cpu utilization never peaks out....I don't know that I have ever seen it hit 100% or even near it. I have actually seen a server load in the 4's with a cpu utilization of 20%

apollo
07-14-2002, 01:58 AM
increase the max allowed concurrent connections for mysql daemon... the default is 30 I believe.... correct me, If I am wrong

ps. always remember, that for VERY HEAVY mysql usage you should have RAID-0. If you don't create many inserts, RAID-1 and RAID-5 will do as well (if read queries from the DB). And of course, SCSI disks! Plus, optimize, optimize and one more time optimize..

bombino
07-14-2002, 03:01 AM
If your load stays at 3 or greater for sustained periods of time, you almost definately need a RAM or CPU upgrade. (or both)

mdrussell
07-14-2002, 06:29 AM
I agree with bombino - a sustained load of 3+ should warrant a definate upgrade, even more so on a celeron cause celerons are not server chips.

How much traffic is this server pushing?

dandanfirema
07-14-2002, 06:35 AM
Server memory upgraded...

Everyone seems to keep focusing on processor, however, if this were the issue, wouldnt I expect to see a high cpu utilization?

apollo
07-14-2002, 08:09 AM
You are using IDE disks, right?

dandanfirema
07-14-2002, 08:16 AM
On that server, yes

apollo
07-14-2002, 08:26 AM
that may be the problem!
But it's really hard to say, is there a way to get ssh access so I can check it out ? I will pm you

dandanfirema
07-14-2002, 08:35 AM
The memory seems to have helped. I am going to let it run a few days before I draw any further conclusions on this server.


Just another one to think about.


I had a cpanel server that I put into service recently. I noticed with NO users defined, no traffic...nothing, that the load would bouce between .5 and .75.

linuxnewbie
07-15-2002, 10:55 AM
wow ive never seen my server load above 0.25 and 99% of the time its at 0.00 0.00 0.00

i push abt 150GB/month and have about 20 users logged on at the same time on forums using mysql db and php...although ram usage and swap usage is very high

so why is my load so low and mem usage very high? anyone?

linuxnewbie
07-15-2002, 11:36 AM
ok i decided to dig up some info:

4:28pm up 18 days, 3:25, 1 user, load average: 0.00, 0.00, 0.00
101 processes: 99 sleeping, 2 running, 0 zombie, 0 stopped
CPU states: 0.7% user, 1.1% system, 0.0% nice, 98.0% idle
Mem: 511648K av, 497436K used, 14212K free, 1352K shrd, 103364K buff
Swap: 1020116K av, 58696K used, 961420K free 226340K cached

what do ya think? how can i improve system performance?

FHDave
07-15-2002, 11:38 AM
From what I can see, your server is not doing anything at all, hence no wonder the server load is 0.00 . If you want to monitor your server load (not just at time when you ssh/telnet into it), use MRTG to plot your server load so you practically monitor it 24/7.

FHDave
07-15-2002, 11:40 AM
Also, you may want to upgrade your memory since you don't have much free memory anymore and the server has started to utilized the swap memory.

linuxnewbie
07-15-2002, 11:44 AM
thanks but i dont understand how i dont have much free ram/swap memory if the server is not doing anything....anyway to flush the ram or something like that?