Perc H710P CTIO Performance

Hello Stephan

This type of test is not going to be a good performance evaluation. The reason adaptive read ahead and caching are blowing away cut through I/O is because the data pool is so small. 280GB is so small that the controller can cache all of it.

When writing it sends the complete/finished command once it hits the cache if cache is enabled. It is not having to write all the way to the SSD to complete the task. This is seen by the very high 550 ms response time on writes with CTIO.

With technology improvements of 6GB/s versus 3GB/s, faster cache, more cache, and faster processors on the controller the gap is being closed on how much they slow the data throughput to an SSD. In a production environment CTIO would likely outperform caching and read-ahead if the same data was not constantly being accessed.

Thanks

280GB is so small that the controller can cache all of it.

How can the controller cache 280GB? It is only offered with up to 1GB of cache?

[quote user="DELL-Daniel My"] 280GB is so small that the controller can cache all of it.

How can the controller cache 280GB? It is only offered with up to 1GB of cache?

[/quote]

Yeah that was poorly worded. I could have done a better job explaining myself. The program doesn't actually use 280 GB. It uses a 1GB file that it manipulates into 280GB of total file testing. The file itself is just 1GB; which the controller can cache. Even though it is manipulated to seem larger the file referenced is within cache. This is a quote from the site for the program(translated from german):

"In Seq-test the program measures how long it takes to read a 1 GB file to write respectively. 4K test the read and write performance is determined at random 4K blocks. The 4K-64 corresponds to the test Thrd 4K procedure except that the read and write operations are distributed to 64 threads. This test should SSDs pose with Native Command Queuing (NCQ), differences between the IDE operation mode where NCQ is not supported, and the AHCI mode. The additional compression test can measure the power of the SSD in response to compressibility of the data. This is especially for the controllers that use to increase the performance and life of the cell compression. Important in the first three synthetic tests and the compression test, the size of the test file 1 GB."