Richard McIntosh, ProSync IT

Tips & Tricks

VMWARE vCenter SQL Server backend

VMWare vCenter can use multiple types of databases for it’s backend, one of these is Microsoft SQL Server Express. This is a popular choice but is intended for small deployments of up to 5 hosts and/or 50 VM’s.

Something to watch out for is that over time this database can fill up with historical performance data and MS SQL Express has a hard limit of 4096MB (4GB) per database.

If you hit this limit vCenter will stop working completely and you will be forced to either move the databases for vCenter over to a different SQL server that does not have that limit or reduce the size of the database.

The easier and quicker of the two options is to reduce the size of the database.

Luckily vmware has created a SQL script to help with this. Make sure you pay attention to the version of vCenter you have and use the proper instructions and SQL script for that version.  Here’s a video from VMWare on how to do it:

How to purge old data from the database used by VMware vCenter Server

Of course if your environment has out-grown or will out-grow MS SQL Express it is a good idea to upgrade the SQL Database server backend to better handle this and prevent this sort of thing in the future.

Another thing you can do is customizing the statistical data collection settings.

From vCenter; click on “Administration”, “VirtualCenter Management Server Configuration”, and select “Statistics”.

To give you an idea of the amount of space this can take up in the database

“Using default settings, the statistical data for 75 hosts running 8-16 VMs per host will plateau around 90-150 MB in a year (200-330 MB if set to “full”). Each month, the average number of events generated will also consume about 190 MB in SQL, and 70 MB in Oracle. Total DB size after a year is expected to be around 2.40 Gb in SQL, and 1.2 Gb in Oracle. “ *data taken from vmware communities post.