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Chrilleee

Member

Registered: 2011-04-27

Posts: 34

RAID1 read/write occasionally stalls

I have just created a RAID1, using two Seagate 2TB disks. I have changed the speed_limit_min and speed_limit_max to have them sync faster (which I believe is reset after a reboot), other than that, the RAID1 config is standard. The disk is also encrypted using dm-crypt (as ar all my disks).

When I copied files to this new RAID, it occasionally stalls for a second or two, and then continued copying. And just recently I took a backup of it, using rsync, to an external disk, and the same thing happened. It stalls occasionally for a second or two.

This does NOT happen between any other disks, only when interacting with the RAID.

Does anyone have any idea on how I can fix this?

Chrilleee

Member

Registered: 2011-04-27

Posts: 34

Re: RAID1 read/write occasionally stalls

Still having this problem and haven't found any fix to it. Anyone who has experienced the same?

frostschutz

Member

Registered: 2013-11-15

Posts: 1,647

Re: RAID1 read/write occasionally stalls

Is there anything in dmesg when it stalls? smartctl -a looks fine and both disks pass a smartctl -t long self-test?

Encryption can cause stalls, if the CPU is sufficiently busy. Although it should not be noticable with AES on a AES-NI system...

nstgc

Member

Registered: 2014-03-17

Posts: 393

Re: RAID1 read/write occasionally stalls

What are you using for the RAID? When I used on-board fake-RAID controller from Intel I frequently had this problem. The solution, for me, was to go pure software RAID.

Also, it may be that the array is stalling due to some kind of snag disk-side. Consumer grade HDDs will try to read from a drive until it absolutely fails to do so, instead of telling the controller to read from another disks/use parity. This, too, can cause stalls, as well as drive drop outs.