[SAC] xblade14 distress

[Christopher Schmidt]

On Fri, Jan 08, 2010 at 11:40:14AM -0500, Frank Warmerdam wrote:
> Folks,
>
> I found xblade14 in distress this morning.  Load average very high, and
> barely responsive.

A series of fixes has alleviated this situation to some extent.

1. The entire reason for this change is the popularity of the new qgis
   release. The qgis website was the culprit for the change in performance.
2. The number of apache children on this server was completely out of line
   with the actual server RAM. Lowering the maximum to 30 leaves the machine
   usable even when the load is high.
3. Once narrowed to qgis, I changed the qgis homepage to a static page,
   and had macha enable caching on the site. This seemed to resolve the
   performance.
4. Changing the homepage to not be static caused it to break again.
5. The homepage had a poll, which no other pages have; this was causing
   80% CPU load when there were a few requests.
6. Removing the poll fixed the performance issues.

The server is now handling reasonable with 30 max apache children, and 
no poll on the qgis Joomla homepage.

The performance will still be somewhat slower than usual; we're doing
2x the number of requests that osgeo1 does currently (6reqs/sec vs. 3reqs/sec)
on average on this server, which is only one small CPU vs. 4 big ones, so
don't kill the machine, but it should be reasonable to use again.

Regards,
-- 
Christopher Schmidt
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