High Resouces Usage Issue

Curtis

Verified User
Joined
Oct 17, 2004
Messages
28
Hi all,

as i see on TOP, sometimes there is a apache process use almost 100% cpu resource. Is that any idea can let me see what this process is doing for? Thanks.
 
You could give the Domain Monitor tool which can be found in the 3rd party forums a try. It will collect information from apache using server-status and store results per domain in a mysql database for use.
 
I have been struggling with the same issue.
But, today we are seeing a completely new situation. Apache's use of memory has suddenly plunged from 2.7% to 0.8%.
This is seen in the following table of results from TOP earler in the day and more recently.

Code:
11340 apache    15   0 21140  13m  16m S  0.0  2.7   0:04.67 httpd
11341 apache    16   0 21176  13m  16m S  0.0  2.7   0:04.21 httpd
11342 apache    15   0 21040  13m  16m S  0.0  2.7   0:10.65 httpd
11343 apache    15   0 21060  13m  16m S  0.0  2.7   0:04.29 httpd


11341 apache    16   0 21144 4188  16m S  0.0  0.8   0:05.71 httpd
11342 apache    15   0 21140 3944  16m S  0.0  0.8   0:12.49 httpd
11343 apache    16   0 21048 3808  16m S  0.0  0.7   0:05.78 httpd
11344 apache    15   0 21164 3832  16m S  0.0  0.7   0:05.88 httpd

To see if this was really true, I accessed the site with the output of TOP displayed in a sshd window. I accessed all the php pages and some of the different sections of the site and memmory usage stayed under 1% per connection.

This is very strange. More so, because I have done nothing in the past couple of hours.
 
There are so many possible causes, ranging from a spike in normal(massive) website usage to a lame DoS attempt.

P.S. - I would not consider 2% highload
You also know how non-windows operating system handle ram usage as well? Even if a program that was using it stopped using it, it is marked as still in use where in fact it is available ;)
 
If Apache only used 2% of available memory, I would not be concerned. When things are quiet we have around 20 simultaneous connections.
If each instance of Apache created to service that connection uses 2-3% of memory, it is using 40-60% of system memory. If usage is under 1% per instance, we are under 20% of system memory.
Once or twice a week, the server load reaches the point where the system freezes.
Today, my biggest surprise was that Apache mysteriously dropped from using around 2.8% of memory per instance to using around 0.8%. The machine has no more RAM and I made no configuration changes.
In a near miss earlier this week, TOP reported we had just 5 megs of memory left -- one http connection away from a system freeze.

This weekend I will double the RAM in the machine. I may also upgrade to Apache2 in the hopes it will be a more efficient user of system resources.

You thought about a lame DoS attack is worth pursing.
 
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