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R/W speed ThunderBay 4 RAID 1+0

Trusted Member Customer

What speed should I expect here?

I am getting 330MB/s write and 290 MB/s read.

I would have expected the reads to be faster then the writes.

ThunderBay 4 RAID (4x4TB Toshiba X300 drives) configured as 1+0 with A/B a mirror pair and C/D a mirror pair.

Topic starter Posted : 17/07/2017 4:54 pm
Member Admin

The challenge with improving read speeds on HDD mirror configurations is anticipating how the disk cache functions.

What happens, is disks "pre-fetch" information, so if we can anticipate what they are fetching, we can leverage that to improve read performance. There is no single pattern that works for all disks, as every disk manages cache, and read-ahead differently.

We built a tool that worked for the majority of shipping disks, but does not work on all disks. We also have to update this occasionally, as drives are constantly changing.

So it appears that the X300 are different in how they handle pre-fetching data.

We will look into this and when we update this feature again, see if we can do something for the X300 series.

thanks for bringing this to our attention.

Posted : 18/07/2017 1:08 pm