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(Relatively) Slow RAID 0 write speeds

TehGiantSlayer
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This is a screenshot of me copying about a hundred files (9 GB total size) inside a RAID 0 drive I'm using.

 

The RAID 0 drive is between two Samsung 850 EVOs, with benchmarks giving me a rated 1000 MB/s sequential read and write speeds.

Not that I'm complaining (but I am :rolleyes:  ), but why are my speeds not surpassing the 500 MB/s mark? I would imagine since these files are not randomly distributed throughout the drive, that they would attain the sequential speeds. Also, can anyone explain the slow rise and sharp fall pattern in the speeds? I've noticed it over several other large copies.

 

Thanks!

post-247478-0-88623700-1438232319.png

post-247478-0-88623700-1438232319.png

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Was the file already on the drives, then copying somewhere else on the drives?

ie, was the source also on the raid?

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Was the file already on the drives, then copying somewhere else on the drives?

ie, was the source also on the raid?

Yes, the source and the destination were both on the RAID drive
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~snip~

 

Hey there TehGiantSlayer,
 
What results are you getting on a regular benchmark on the RAID array? Transfer speeds may vary depending on the location of thefiles, the number and the size and even the load of the computer parts as well as what the exact parts are. I would stick to the benchmark to get a real idea of the RAID is functioning as it's supposed to. Try copying one large file and see if the speed is the same or larger. It wouldn't hurt to check the drives' health.
 
Captain_WD.

If this helped you, like and choose it as best answer - you might help someone else with the same issue. ^_^
WDC Representative, http://www.wdc.com/ 

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Hey there TehGiantSlayer,

What results are you getting on a regular benchmark on the RAID array? Transfer speeds may vary depending on the location of thefiles, the number and the size and even the load of the computer parts as well as what the exact parts are. I would stick to the benchmark to get a real idea of the RAID is functioning as it's supposed to. Try copying one large file and see if the speed is the same or larger. It wouldn't hurt to check the drives' health.

Captain_WD.

Thanks for your input.

Off the top of my head, I remember the sequential read and write speeds to be 1000 MB/s, but I don't remember the other speeds.

I will attempt to copy one large file, and I'll also make sure to post the benchmarks of the drive soon. Also, I doubt the drive is unhealthy, as I bought it two or three weeks ago, but I will check, just to make sure.

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...

 

First screenshot is of one 34 GB ISO file, source and destination in drive.

 

Only had time for these before having to head to uni.

post-247478-0-73850200-1438267534.png

post-247478-0-01984100-1438267535.png

post-247478-0-73850200-1438267534.png

post-247478-0-01984100-1438267535.png

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~snip~

 

The speed is indeed rather lower. I'd check if the proper and latest updates are installed both for the controller and the drives. Contacting the manufacturer of the drives can also be of use as they can give yo some additional info and tips. :)
 
Captain_WD.

If this helped you, like and choose it as best answer - you might help someone else with the same issue. ^_^
WDC Representative, http://www.wdc.com/ 

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The speed is indeed rather lower. I'd check if the proper and latest updates are installed both for the controller and the drives. Contacting the manufacturer of the drives can also be of use as they can give yo some additional info and tips. :)

Captain_WD.

Okay, I'll do that as soon as I get the chance!
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