Increase vBulletin and WordPress MySQL speed by using fast SSD drives

I’ve been consulting owners of very large blogs for a few years now and the last client was a very popular tech blog owner who’s web site has over 3.000.000 monthly visitors.

The server hardware specification:
8GB RAM
4 CPU Intel E5640 (16 cores in total)
1TB SATA HDD

This WordPress powered blog runs on LAMP platform with Nginx (my favorite!) front-end server, Apache and MySQL on one physical server. The problem was IO load – the IO time wait as reported by “iostat” utility was sometimes over 26%. The average server load was over 8 all the time, while CPU usage reported 80%+ CPU idle time. The WordPress blog performed quite well (caching rocks!), but vBullet was performing much slower with up to 10-15 seconds of delay to display latest posts. The backups were very slow as well. Administration of the server via shell was not that pleasant either… file operations took long delays and performing “sync” command hang up the shell for over 30 seconds…. IO was the problem. It was unacceptable as some of the web visitors were complaining about the forum speed.

After checking the upstream provider web page, we noticed that SSD hard drives are offered as extra add-ons. We thought we should install one SSD hard drive and see if it decreases the IO load to acceptable levels or perhaps go with SAS RAID configuration. We contacted the upstream provider and after a few days a INTEL SSDSA2M120 SSD hard drive was installed in the box. First, we moved web file folders and all logs to SSD hard drive, but the server load decreased a little. The MySQL tuning utility reported very heavy temporally table creation and heavy reads on device were MySQL datadir resides.

The next step we did was to move MySQL datadir and temp folder to SSD hard drive. The load dropped to 2-3, IO wait dropped to 0.25-0.36% (!!) and vBullet performance increased multiple times.

The backups and MySQL dumps are very quick now, the server load decreased a lot and IO wait is close to zero. SSD hard drives really rock and I highly recommend these super fast drives if your server has IO bottleneck.


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