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Workstation Pattern

The Workstation pattern emulates a user who’s working in various applications in the NTFS5 file system:

It’s simple with the RAID0 arrays: the more disks an array has, the faster it processes the requests. The RAID1 is far faster than the single drive, and the RAID10 is everywhere a little but faster than the two-disk RAID0. The RAID5 and RAID6 aren’t very fast because the Workstation pattern has quite a lot of random write requests which slow those arrays down considerably.

We’ll calculate the performance ratings of the different RAID arrays for the Workstation pattern by the following formula:

Performance = Total I/O (queue=1)/1 + Total I/O (queue=2)/2 + Total I/O (queue=4)/4 + Total I/O (queue=8)/8 + Total I/O (queue=16)/16 + Total I/O (queue=32)/32

Quite expectedly, the pattern’s having random write requests has led to the RAID5 and RAID6 arrays being slower even than the single drive. The RAID0 arrays line up according to the number of disks per array. The mirrored RAID10 is slower than the three-disk RAID0. The RAID1 has been faster than the single drive everywhere except under linear load, but in our performance rating the result under a shorter request queue has a bigger weight. That’s why the performance rating of the single drive is higher than that of the RAID1.

 
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