I am attempting to boost the performance of some spinning disks by using Intel Cache Acceleration Software.
Using a write through process the software can place the contents of folders/files you specify in cache. When the file is next requested it can be quickly pulled from the cache rather than going to the slow spinning disk. This can result in major speed improvements of disk reads. Great for caching spinning disk content or network based storage.
In my specific case I have a fairly small amount of cache, only 124 gigs of PCIe SSD storage. I am allocating 100% of that space to cache the MySQL data folder, which in theory is making 100% of my database available from the cache because my data folder holds only 116 gigs of data.
The software integrates into Windows Performance Monitor so you can easily view how much data is in the cache, the % Cache Read Hits/sec and other good stuff.
While monitoring those stats and doing queries against the database, perf mon was not showing hits to the cache… what’s going on? Time to investigate and benchmark a few things.
There is really no configuration options in the caching software. The only setting is something called 2 Level Cache and you can select on or off – that’s it. There is not much information about what that is for, and it is not intuitive based on the label.
I am going to run three simple tests, which should reveal how much of a performance the cache makes and if I am better off running with this 2 Level Cache on or off.
Test #1
Restore & Backup 96gb Database With No Caching
Restore Time: 5 hours 49 minutes
Backup Time: 1 hour 03 minutes
Test #2
Restore & Backup 96gb Database With Caching – Level 2 Cache Off
Restore Time: 5 hours 56 minutes
Backup Time: 0 hours 53 minutes
Test #3
Restore & Backup 96gb Database With Caching – Level 2 Cache On
Restore Time: 6 hours 07 minutes
Backup Time: 0 hours 53 minutes
The purpose of the restoration before the backup is to give the cache time to populate. In theory all the database data on disk should be available to the cache, however I have no way to verify that it is all in cache or not.
The results? WOW! Can you say disappointed? What is going on here?