SQL Server Timeout issues at random times causing performance degradation

Question

I am having random timeout during a brief period of time on certain days. My CPU, Memory looks fine. So I ran Performance Monitor during these spikes and found my average disk sec/read was 5.8 seconds for that 10 minutes. What can I take from this? Can SQL server cause this because of expensive queries, or is it a disk issue? I am in the cloud on a SAN and they said I am the only one having this issue, but I also maybe the only one getting a large amount of users hitting my site.

Solution

It could be a lot of things. This could help you nail down what's causing it...

http://www.sqlshack.com/sql-server-performance-monitoring-data-collector-part-3-reading-reports/

One thing to note, if disk reads are your issue (meaning its not a query you can optimize further) then one of the easiest things you can do to alleviate it, is provide more RAM to SQL. The closer you get to fitting your DB into memory, the less likely you'll need to read from disk. For some, fitting all your DB in memory isn't an option, but the more memory the better.

Secondly, if it's a web app that's causing the issue, and its data that is called frequently, another additional option could be to put a caching system in like MemCache, Reddis or AppFabric.