Very slow copying


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We have a gen8 HP Microserver with quad core Xeon CPU and 6gb of ecc ram  with a 3 HDD array and parity drive with UNRAID O/S obviously, all working fine but when we send files such as movies or copy files the write speed starts at 112mb/s for about 30 seconds then it drops to 10mb/s for the rest making the copying of files painfully slow, can anybody advise on how to improve this please?

Many thanks


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35 minutes ago, doppelt said:

and option is dangerous if you losing power - all data go to nirwana.


Only if you don't have an UPS, and you should have one.


35 minutes ago, doppelt said:

its still copying with 10 mb/s - no improvement.


Try turbo write or post your diagnostics after a copy.



Edited by
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thanks - very good.


I did modification without a restart. Is one necessary ?


this at least improved performance from 10 to about 23-26 MB/s.


I´m not that familar with Linux systems.
What I absolutly don´t get is that reduce in speed after that 30 secs.
Is it depending on the parity disk ?


I had a xpnology running on the machine before and would like to change OS because of weak support of the cpu by 2 Cores.

Ok, it was a JBOD System without any array and parity drive.

But never would have thought about that difference in speed !


And sorry, english is not my mother language and every explanation has to be read twice. There also could be a few misspellings - please be patient.


btw: nice forum and i feel home after that only 5 postings

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Nothing obvious, disk2 is showing a couple of pending sectors, possibly false positives and don't appear related to your problem.


1 hour ago, doppelt said:

but we are talking about sata 3 wd black - its a laugh for that hdds to write that speed !


Your parity disk is an older WD green, and that will be slower than the others, unRAID can't write faster to the data disks then it can write to the parity disk, still I would expect better speeds than you're getting, as long as all disks are healthy.


If write cache is already enable in the bios maybe run diskspeed to check if all disks performance is normal, or try temporailly disabling parity and write to a couple of disks to confirm if there's no other issues.

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1 minute ago, doppelt said:

could not be a problem of the wd green.


It also proves it's not an unRAID problem, as without parity data disks behave just as a single disk in Linux , double check write cache is enable, can't think of another logical reason, or there's another hardware issue somewhere.

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Make sure that the sending PC has the latest drivers for the NIC chip set.  I had issues with transfer speeds that I traced to outdated RealTek NIC drivers on my Win7 computers!


EDIT:  If that is not the issue, Reboot all switches and Routers on the network.  (All of those contain little computers and a occasional reboot will sometimes 'fix' problems by re-initializing everything.)

Edited by Frank1940
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