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Disc I/O more than 98% If I run Wordpress site on Dedicated Server
Disc I/O more than 98% If I run Wordpress site on Dedicated Server. I am using apache and kloxo Mr. so please tell me how to solve this error... [ http://imgur.com/G4kM7oC ], [ http://imgur.com/DRCybVh ].
It happening only if i run wordpress site. Not a server or disc problem because if i chnaged server , same issue with new server also. Issue arises if i add wordpress based site. so please help me.
Comments
Hardware specs and raid config?
Get a new wp installation.....possibly infected....
I remember debugging some slow wordpress site in the past and turned it out that it was doing some 3000+ database selects just to show the front page. There is a setting how many posts to show per page and the site owner had it set to 3000...
It usually happens if your server can't handle your website. The best way to go is to optimize website or find better server for it. If you're fine with payed help - pm me. I can either optimize your website or host your website on my hardware in case if your website is highloaded.
Do you have any WP caching plugins?
Use wp redis
Already looked what service is actually responsible for the I/O? Have a look using 'iotop'.
High I/O load can be caused by many things - from swap usage to services that need optimization.
Standard apache / mysql configs are pretty horrible, and in pretty much all cases these use the system resources not the most efficient way.
You can get a lot of performance increase by tweaking the apache / mysql services to your website needs.
In top of that start something simple like 'opcache' (or xcache when your running an older php version).
If you have high I/O load due to mysql, and you can't get it solved by optimizing the service, you'll probably running on sata disks. Look for an SSD in such case.
Just start with diagnosing first and look if configurations of apache / mysql need some tweaks :-)
Probably kloxo the issue
Problem is likely a really shitty plugin with high MySQL usage because of horribly formed queries that cause tons of joins and selects to be done in tmpdir. tmpdir is default located in the /tmp dir and will use tons of IO during joins and large queries. You should consider using memory for your joins and selects, tmpdir=/dev/shm for example.
People need to realize when they buy cheap shitty plugins that the authors are not producing them for large sites, write really shitty queries and their code usually doesn't build indexes correctly. If you scale your site you will need some DBA skills and to understand how to make indexes as needed to assist with this. Failure to understand how to maintain your database and create indexes will results in a ton of abusive IO usage like you are seeing because the MySQL server is constantly using the /tmp dir for joins, etc.
Also, there is a bug more recently released in some versions of WordPress which cause issues with wp_options tables and cause a lot of garbage requests: https://core.trac.wordpress.org/ticket/33423 for which there is a hotfix: https://wordpress.org/plugins/wp33423-hotfix/
If any of this doesn't make sense to you or you still don't understand, please hire a developer to help you, any developer worth their salt should know how to resolve the issues you are seeing quickly.
Hopefully this helps you out.
Cheers!
+1 , exactly to the point.
and even it is not mysql-related, then it's probably a shitty plugin causing a lot of ajax requests which require php to be loaded and so on...
Have you tried optimizing MySQL?
Maybe run Mysqltuner which is a fairly easy low effort first step. Don't take the recommendations as gospel but it might point out something worthwhile.
https://github.com/major/MySQLTuner-perl
Also check all your databases for corruption using
mysqlcheck -c -u root -p --all-databases.I have also seen other hard to find things cause this. Like a log file that cannot be written to because it's missing or the permissions or corrupted. Also Apache can do this due to permissions.
Check you logs, is someone hitting wp-login.php or xml-rpc? When I used to use Apache with Wordpress I would see cpu usage skyrocket to 100% if someone was bruteforcing wp-login (which happens very often if you don't protect it, bots will constantly hit it even if you just setup a wordpress site). Are there any php errors that are repeating over and over again in your logs?
Or like others have said, what plugins are you using? Badly coded plugins can cause all sorts of issues.
Nowadays I use Nginx and allow access via my ip only to wp-login and deny access to xmlrpc (or rate-limit it if I need to use a plugin that requires xmlrpc).
Around 7PM, you seem to have run out of physical memory and the OS started swapping.
Though, this graph, or behaviour of your OS is questionable, i.e. the physical memory is not used up and the swap is utilized; I think you'll need better tools to analyze your situation.
How much RAM do you have in this server?
What is your web server, mysql and php configuration?
I nearly fell on this one too. but probably the light pink area is just highlighting the time period and does not equal to swapping like the graph may suggest on the first blink.
the same highlighting happens on the other graphs too (where there is no swap involved at all ;-))
Do you have evidence?
@mustafaramadhan its a wordfense security plugin isssue.... But if i not use that plugin someone adding code in my heade.php so is there any other way to avoid this??
Cloudflare + ithemes security?
@shovenose i am using cloudflare but not using itheme security plugin...
Decreasing 'Update interval in seconds (2 is default)' from '2' to '10' or more (I am using '30').