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Raid transfer speed inquiry

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Anhtu Vu
Raid transfer speed inquiry
on May 11, 2019 at 3:06:03 pm

On my Z840, i have an internal 3 disks raid 0 (speed = 350MB/s) and external SAS Raid 0 (550 MB/s). The Atto SAS card is on a PCIe x 16 slot.

When i transfer large files (800 GB), the transfer speed is roughly 160 MB/s and the system says it will take roughly 1 hour. This seems slow considering the speed of my Raids. Any idea why ?

Midway into the transfer, the transfer slows down and system shows 5 hours til completion before returning to previous speed with 55 min til completion message...any idea why ?


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Rainer Wirth
Re: Raid transfer speed inquiry
on May 14, 2019 at 12:36:03 pm

Hi Anhtu,

you can test write, read speed with Aja speed test.
Surprisingly you work with Raid 0, which is a bit harakiri.
If one disk fails you end up with a total data loss.
For video editing the read speed is always higher than the write speed.
If your SAS system is nearly full the speed goes down on a significant level.
The PCIx Slot is not your bottleneck. Even with x8 you should get more data speed out of your SAS system.
It should be around 700 MB per second.

This should answer your question.



Rainer Wirth
Mac pro 8core
several raid systems

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