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Disk Response Time

IOMeter is sending a stream of requests to read and write 512-byte data blocks with a request queue depth of 1 for 10 minutes. The disk subsystem processes over 60 thousand requests, so the resulting response time doesn’t depend on the amount of cache memory.

The HighPoint controller is obviously better when reading from the mirror arrays. However, it also has a worse result with the single drive, with a rather big gap.

It is simpler at writing: the HighPoint always has a lower response time, processing disk requests in a more efficient way.

The Promise controller is considerably better with RAID0 at reading but its writing speed is lower with every type of RAID0.

The controllers’ behavior with RAID5 is similar to that with RAID0: the Promise is far better at reading and worse at writing. The HighPoint controller seems to be faster at processing write requests. Take note of the performance of the degraded arrays: both have the same response time at writing as the ordinary arrays (this is normal because the situation doesn’t change from the controller’s point of view) but have a considerably higher response time at reading.

The Promise is also much better than its opponent at reading when it comes to the more complex RAID6 array type. The HighPoint behaves somewhat oddly: the response time of the degraded minus-one array is worse than the response time of the minus-two array. The HighPoint is still better at writing, especially with the degraded arrays. Interestingly, the response time increases not only at reading but also at writing when this array type degrades. You can see this with each controller.

 
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