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Web-Server, File-Server, Workstation Patterns

The drives are tested under loads typical of servers and workstations.

The names of the patterns are self-explanatory. The Web-Server pattern emulates a server that receives read requests only whereas the File-Server pattern has a small share of write requests. The request queue is limited to 32 requests in the Workstation pattern.

The order of tests has no effect on the performance of the controller in this group of tests. Therefore we will only show one test cycle in the diagrams below.

The number of disks in the array is the crucial factor when the load consists of reads only as in this test. If there are no additional factors, of course. Of such factors we can name the algorithm of selecting a luckier disk in the RAID10 that helps this array win and some problems of the RAID50 at request queue depths of longer than 16 that make it slower than the other arrays.

Under mixed load the standings are not so obvious. The RAID10 is ahead short queue depths but gives way to the RAID0 at long ones. However, the RAID10 has the highest overall rating according to our formula. The RAID5, RAID6 and RAID50 arrays go neck and neck at short queue depths but the RAID5 goes ahead at longer queue depths whereas the RAID6 falls behind the RAID50.

The Workstation load is more complex and we do not consider queue depths longer than 32 requests. As a result, the RAID10 is again in the lead while the RAID50 is somewhat faster than the RAID5. Both of them are much faster than the RAID6. When there is a lot of writing to be done, calculating two checksums affects the latter array’s performance most negatively.

If the test zone is limited to the initial 32 gigabytes of storage space, the results grow up. The resulting zone on the disks is very narrow, so the luckier disk selection algorithms do not provide a big advantage for the RAID10. The RAID0 is on top as the result.

 
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