zpool scrub speed

Nils Bausch nils.bausch at googlemail.com
Fri May 20 14:45:00 EDT 2011


Hi Steve,

crumbs, if that is so, then I have no choice to migrate to a ashift=12
version once I have enough drives to move the data around :/
I will try setting those variables in the module next and take a look
if it makes a difference.
Many many thanks.

cheers,
Nils

On May 20, 6:59 pm, "Steve Costaras" <stev... at chaven.com> wrote:
> Thanks, ok, so you created the pool with all drives initially (didn't add another vdev or anything later).
>
> The drive you mention may show 512b sectors however this line:
>
> "Drive Configuration 512 bytes per sector with Emulation" athttp://www.samsung.com/latin_en/consumer/monitor-peripherals-printer/...
> seems to imply that it may be 4K internally and just 'lying' to the os. (same thing I see with a lot of newer drives so it's hard to tell).
>
> A couple things that may help. First you can try decreasing the zfs_vdev_max_pending to 1 (default is 10) (assuming Brian has this as a passable variable?)
>
> echo "1" > /sys/module/zfs/parameters/zfs_vdev_max_pending
>
> Other item would be to modify or pull a new version of zpool and create a new pool with ashift=12 opposed to ashift=9 (4KiB opposed to 512b). (unfortunatly this would require re-creating the pool from scratch).
>
>
>
> -----Original Message-----
> From: Nils Bausch [mailto:nils.bau... at googlemail.com]
> Sent: Friday, May 20, 2011 11:44 AM
> To: 'zfs-discuss'
> Subject: Re: zpool scrub speed
>
> ....
>  pool: wtf
>  state: ONLINE
>  scan: scrub repaired 2K in 14h54m with 0 errors on Thu May 19
> 10:27:15 2011
> config:
>
>         NAME STATE READ WRITE CKSUM
>         wtf ONLINE 0 0 0
>         raidz1-0 ONLINE 0 0 0
>         ata-SAMSUNG_HD154UI_S1XWJ1KSB33767 ONLINE 0 0 0
>         ata-SAMSUNG_HD154UI_S1XWJ1KSB33765 ONLINE 0 0 0
>         ata-SAMSUNG_HD154UI_S1XWJ1KSC11001 ONLINE 0 0 0
>         ata-SAMSUNG_HD154UI_S1XWJ1MSC01749 ONLINE 0 0 0
>
> errors: No known data errors
>
> > And what type of drives are these (i.e. are they 4KiB sector sized drives internally?)
>
> Model Family: SAMSUNG SpinPoint F2 EG series
> Device Model: SAMSUNG HD154UI
> 1.5 TB and they have 512 bytes as sector size.
>
> Thanks,
> Nils



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