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Speed up RAID Rebuild?

PostPosted: Wed Apr 30, 2014 3:35 pm
by basketballmail2
Hi guys

Is there a way to speed up the Rebuild of a failed RAID? It seems to me that the NAS puts a very low priority on rebuilding as it is telling me it will take about 3 Days to rebuild my 4 TB RAID 1. Is there a way to tell the NAS to speed it up? I get that it doesn't need to be fast when you build a new RAID but when you are recovering from a failed drive you do rather want your raid back up and running quick and not wait 3 days.

Thanks

Cedric

Re: Speed up RAID Rebuild?

PostPosted: Wed Apr 30, 2014 5:26 pm
by orion
You can try to increase the value /proc/sys/dev/raid/speed_limit_min which sets the minimum speed in KB / sec. Oh, you can use ssh to change the value by:
Code: Select all
cat /proc/sys/dev/raid/speed_limit_min
echo 120000 > /proc/sys/dev/raid/speed_limit_min

And it's better to make sure speed_limit_max value is higher than speed_limit_min. :)

Re: Speed up RAID Rebuild?

PostPosted: Wed Apr 30, 2014 5:33 pm
by basketballmail2
Sweet thanks I'll give that a try as soon as I'm home from work! I see I really got to learn more linux to get the most out of my NAS experience ;)

Re: Speed up RAID Rebuild?

PostPosted: Wed Apr 30, 2014 10:42 pm
by basketballmail2
Wow, what a speed increase :) Thanks! what if I put the max and min up even more than the 120000 do I risk crippling something or will I just eventually reach the max speed of the drive and that is it?

Re: Speed up RAID Rebuild?

PostPosted: Fri May 02, 2014 10:46 am
by orion
That should reach the max speed of your drive (depends on your HDD type). It will utilize more CPU power and memory. That should be fine. Maybe, impact to the response speed of UI.

Re: Speed up RAID Rebuild?

PostPosted: Tue Nov 12, 2019 5:45 am
by Ubuntux
Nice info! I was wondering if my NAS was slow, rebuilding Raid1 with 75 MB/s and using this code i was able to see that the max speed is 200 MB/s so either my WD Red drives are slow or my AS-604T is slow.. I tried to set the max value to 25000 and the raid rebuild went down to 25 MB/s and set it up for 200000 then it hit back up on 75 MB/s...

Re: Speed up RAID Rebuild?

PostPosted: Sat Jan 04, 2020 11:57 am
by botics
How are you accessing the NAS system files? I would like to do this too.

Re: Speed up RAID Rebuild?

PostPosted: Mon Jan 06, 2020 10:09 am
by orion
botics wrote:How are you accessing the NAS system files? I would like to do this too.

You should enable ssh service on NAS (ADM web -> Services -> terminal services / ssh). Then use ssh tool on your computer, login with root account (password is the same as admin).