Re: ZFS - Abyssal slow on copying

On 2016-10-02 15:25, O. Hartmann 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.
> 
> The drive sounds like hell, the heads are moving rapidly. The copy speed is incredibly
> slow compared to another box I usually use in the lab with UFS filesystem only (different
> type of HDD).
> 
> The whole stuff the nanbsd is installed from and to is on a separate ZFS partition, but
> in the same pool as everything else. When I first setup the new partitions, I switched on
> deduplication, but I quickly deactivated it, because it had a tremendous impact on the
> working speed and memory consumption on that box. But something seems not right since
> then - as I initially described, the copy/initialisation speed/bandwith is abyssal. Well,
> I also fear that I did something wrong when I firt initialised the HDD - there is this
> 125bytes/4k block discussion and I do not know how to check whether I'm affected to that
> or not (or even causing the problems) and how to check whether DEDUPLICATION is
> definitely OFF (apart from the usual stuff list features via "zfs get all").
> 
> As an example: the nanbosd script takes ~ 1 minute to copy /boot/loader from source to
> memory disk and the HDD makes sounds like hell and close to loosing the r/w heads. On
> other boxes this task is done in a blink of an eye ...
> 
> Thanks for your patience,
> 
> Regards,
> oh
> 

Turning deduplication off, only stops new blocks from being
deduplicated. Any data written while deduplication was on, are still
deduplicated. You would need to zfs send | zfs recv, or
backup/destroy/restore to get the data back to normal.

If the drive is making that much noise, have you considered that the
drive might be failing?

-- 
Allan Jude