Dedicated server crashed with few sites

Monday 04 January 2010 1:31:37 pm

I have seen the same happend with just 1 eZ site. We released a portal for registrations. I noticed something was wrong the minute i released the site. As soon the users started logging in and registering the server went nuts. It all crashed within an hour. We fixed this with some code changes on cache blocks etc. But the main fix was adding a php accelerator and tuning both mysql and php. After a couple hours we had the site back up and running again. I would first look into the php accelerator for your server. We use APC. Also check if php got enough memory, and check for tuning on mysql. If possible move mysql to another server, it will take some of the load off. Logged in users doing lots of stuff in eZ seems to be very power hungry. There should be lots of posts here in the forums about tuning php and servers.

These are what i found that might be usefull:

• APC
• Tuning MySQL
• Identifying Trouble Spots by Debugging
• Practical Cache and Template Solutions

Other things you should consider:

• Upgrading eZ to a later version. 4.2 seems to run allot easier than 4.0.1 was. (just upgraded a large site)
• Adding Varnish to the sites

Hope some of this help.

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Høgskolen i Lillehammer
Lillehammer University College
http://www.hil.no
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Messenlien IT
http://messenlien.com
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Wednesday 06 January 2010 2:13:02 pm

Hi John

What about Apache max_clients ? Try to tune it (here's a tiny tutorial ;)).

Can you be more precise on your server configuration please ? PHP/Apache/MySQL/eZ Publish versions, PHP configuration (memory_size, APC config if you have it...). Is Apache in prefork mode ? Is PHP compiled as a module ? Do you run your server on Linux (which distro) ?

Also, you should try to install monitoring tools such as Cacti or Nagios.

You can monitor your eZ Publish websites with jvMonitoring (simple, you can develop new handlers) or eZSNMPd.

First things to check for performance :

• Cache configuration (is view cache activated, did you disable INI File mtime check in config.php, are your cache blocks in pagelayout efficient, ...)
• Opcode cache such as APC (highly recommended, with 128MB at least)
• A reverse proxy cache eventually, such as Varnish

Hope this helps :)

Friday 08 January 2010 1:35:30 am

Hi John

OK everything seems fine with your cache config. Also check if DevelopmentMode is disabled ([TemplateSettings]).

About config.php stuff, it's from eZ Publish 4.1. You can consider upgrading to 4.2 (huge performance improvements) ;)

Friday 08 January 2010 9:44:20 am

A couple of hints:

- mysql queries might be killing your app. You can find out how many queries are executed per-page by enabling the debug output (it can be done without disabling caches) and looking at the bottom of the page for the table line that reads "Mysql_queries" (or Mysqli_queries). Anything above 100 is plain suicide. Below 10, you'r gold.

- disabling view cache on hp is a bad idea, really.

You can set it to eg 10 minutes if you want latest news appearing, just not in real time:

<span>{</span><a href="http://doc.ez.no/set-block" mce_href="http://doc.ez.no/set-block" target="ez_no_documentation"><span>set-block</span></a> <span>scope</span><span>=</span>root <span>variable</span><span>=</span>cache_ttl<span>}36</span>0<span>{</span><span>/</span><a href="http://doc.ez.no/set-block" mce_href="http://doc.ez.no/set-block" target="ez_no_documentation"><span>set-block</span></a><span>}</span>

You can use a cache block where you put in the "keys" param a random value calculated between eg 1 and 10 if what you want is some random pictures - you will have the cache block executed about 10 times before it is fully warmed, and successive hits will not execute it anymore

If your news do not update very often, even better than a periodic expiry is one based on actual linking of content editing action with cached expiration. look up the docs about the "smart view cache" for that

- a lot of developers always fetch the current node in the pagelayout, because it is not there and they need just a bit of info from it. Do not do it, use the persistent_variable instead (look it up in the forums/docs)

- make sure your cache blocks are properly tuned: if they do not depend on content expiration, use "ignore_content_expiry", if they depend on expiration on a particular node, set it in "subtree_expiry", and do not forget plain "expiry" timeout (http://ez.no/doc/ez_publish/technical_manual/4_x/reference/template_functions/miscellaneous/cache_block)

Principal Consultant International Business
Member of the Community Project Board

Friday 15 January 2010 1:42:42 am

Sorry, I do not understand fully your request.

If you want the homepage expired every day event if no editing action has been happening, you can set up a cronjob that expires its cache. The php call to expire the cache of an object is:

 eZContentCacheManager::clearContentCache( $contentObject->attribute('id') );

Principal Consultant International Business
Member of the Community Project Board

Tuesday 19 January 2010 7:06:58 am

Anyone ??