very slow transfer rates on move

Support and Discussion for HFR2-SU3S2 ProRaid - For PC Users

very slow transfer rates on move

Postby TheoLeo728 » February 14th, 2017, 10:12 am

I own 5 pro-boxes, 2 HFR2-SU3S2 and 3 HF2SU3S2, all in Raid 5 configuration. When moving files between 2 pro-boxes, Windows 10 averages 10 to 30 MB/s. The maximum transfer data for USB 2.0 is 60 MB/s and USB 3.0 is 640 MB/s. Why are my Pro-boxes slow ?
Probox transfer rate.png
windows 10
Probox transfer rate.png (10.25 KiB) Viewed 561 times
Posts: 1
Joined: February 14th, 2017, 9:47 am

Re: very slow transfer rates on move

Postby WillowViney » May 13th, 2017, 9:11 am

Best guess: Your RAID is fragmented. Drives have sequential transfer rates that are 50-100X faster than a decade ago, but the random seek times are typically only 2X faster since then (around 6-10ms), about 100-166 I/O operations per second. With a 4K block size on Advanced Disks that is only 0.40 to 0.68 MB/second. The makes random I/O something like 200 times slower than the sequential I/O (typically 100-150 MB/s). Therefore it is really important to defrag RAID on Windows because of the huge variation in speed between random and sequential writes.

Always defrag your RAID regularly. This is especially important if you do a lot of writes over time, which I am guessing you are doing since your screenshot shows high-def film .mkvs being copied around for presumably a DVR-type application.
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Joined: May 13th, 2017, 8:54 am

Re: very slow transfer rates on move

Postby Robert812003 » June 14th, 2017, 11:17 am

I noticed the same slow transfer using my 4-bay ProRaid enclosure. Fragmentation may be one reason, but I suggest you try the following:

Open device manager and locate the ProRaid Drive. Right click the drive and go to properties. Click the policies tab. Under "Removal Policy" make sure that the "Better Performance" option is chosen, and not the "Quick Removal" option. Save the settings and test your transfer speed.

Doing this doubled the transfer speed of my ProRaid enclosure. Just keep in mind that it also increases the chances of the enclosure experiencing unsafe hardware removal when turning off.
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Joined: June 14th, 2017, 10:59 am

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