Re: ZFS - Abyssal slow on copying

From: O. Hartmann <ohartman_at_zedat.fu-berlin.de>
Date: Sun, 30 Oct 2016 13:41:44 +0100
Am Tue, 4 Oct 2016 12:42:32 +0200
Fabian Keil <freebsd-listen_at_fabiankeil.de> schrieb:

> "O. Hartmann" <ohartman_at_zedat.fu-berlin.de> wrote:
> 
> > Running 12-CURRENT (FreeBSD 12.0-CURRENT #32 r306579: Sun Oct  2 09:34:50 CEST 2016
> > ), I have a NanoBSD setup which creates an image for a router device.
> > 
> > The problem I face is related to ZFS. The system has a system's SSD (Samsung 850 Pro,
> > 256GB) which has an UFS filesystem. Aditionally, I have also a backup and a data HDD,
> > both WD, one 3 TB WD RED Pro, on 4 TB WD RED (the backup device). Both the sources for
> > the NanoBSD and the object tree as well as the NANO_WORLDDIR are residing on the 3 TB
> > data drive. 
> > 
> > The box itself has 8 GB RAM. When it comes to create the memory disk, which is ~ 1,3
> > GB in size, the NanoBSD script starts creating the memory disk and then installing
> > world into this memory disk. And this part is a kind of abyssal in terms of the
> > speed.  
> 
> Can you reproduce the issue if you replace the memory disk with
> a zvol or tmpfs?
> 
> While I agree that depulication could be the cause of the problem,
> it probably wouldn't hurt to rule out a memory-disk related issue
> before recreating the pool.
> 
> Fabian

I guess this issue was triggered due to having deduplication enabled on the ZFS pool
rather than on the ZFS partitions (this is a guess based upon comments made by knowing
people and the fact, that the noisy copying and slowness went away after removing dedup
from the ZFS pool).

Received on Sun Oct 30 2016 - 11:41:52 UTC

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