endless zpool scrub?

[Goran Lowkrantz]

--On November 26, 2008 12:12:50 +0200 Andriy Gapon <avg at icyb.net.ua> wrote:

>
> I noticed that zpool scrub on a certain pool runs "like forever".
> I decided to monitor its progress using periodic zpool status command,
> once in 10 seconds.
> Here's a snippet from the capture around an interesting point.
> Please notice two highlighted reports ('oops').
> This is stable/7.
> Thank you in advance for insights/comments.
>
>
>    pool: tank
>   state: ONLINE
>   scrub: scrub in progress, 78.87% done, 0h31m to go
> config:
>
>          NAME        STATE     READ WRITE CKSUM
>          tank        ONLINE       0     0     0
>            ad6s2d    ONLINE       0     0     0
>
> errors: No known data errors
>    pool: tank
>   state: ONLINE
>   scrub: scrub in progress, 78.94% done, 0h31m to go
> config:
>
>          NAME        STATE     READ WRITE CKSUM
>          tank        ONLINE       0     0     0
>            ad6s2d    ONLINE       0     0     0
>
> errors: No known data errors
>    pool: tank
>   state: ONLINE
>   scrub: scrub in progress, 78.97% done, 0h31m to go
> config:
>
>          NAME        STATE     READ WRITE CKSUM
>          tank        ONLINE       0     0     0
>            ad6s2d    ONLINE       0     0     0
>
> errors: No known data errors
>    pool: tank
>   state: ONLINE
>   scrub: scrub in progress, 0.00% done, 233h25m to go
> config:
>
>          NAME        STATE     READ WRITE CKSUM
>          tank        ONLINE       0     0     0
>            ad6s2d    ONLINE       0     0     0
> ****oops, went back to 0%****
>
> errors: No known data errors
>    pool: tank
>   state: ONLINE
>   scrub: scrub in progress, 0.00% done, 259h47m to go
> config:
>
>          NAME        STATE     READ WRITE CKSUM
>          tank        ONLINE       0     0     0
>            ad6s2d    ONLINE       0     0     0
>
> errors: No known data errors
>    pool: tank
>   state: ONLINE
>   scrub: scrub in progress, 0.00% done, 186h50m to go
> config:
>
>          NAME        STATE     READ WRITE CKSUM
>          tank        ONLINE       0     0     0
>            ad6s2d    ONLINE       0     0     0
>
> errors: No known data errors
>    pool: tank
>   state: ONLINE
>   scrub: scrub in progress, 0.00% done, 186h45m to go
> config:
>
>          NAME        STATE     READ WRITE CKSUM
>          tank        ONLINE       0     0     0
>            ad6s2d    ONLINE       0     0     0
>
> errors: No known data errors
>    pool: tank
>   state: ONLINE
>   scrub: scrub in progress, 0.00% done, 306h30m to go
> config:
>
>          NAME        STATE     READ WRITE CKSUM
>          tank        ONLINE       0     0     0
>            ad6s2d    ONLINE       0     0     0
>
> errors: No known data errors
>    pool: tank
>   state: ONLINE
>   scrub: scrub in progress, 0.00% done, 292h19m to go
> config:
>
>          NAME        STATE     READ WRITE CKSUM
>          tank        ONLINE       0     0     0
>            ad6s2d    ONLINE       0     0     0
>
> errors: No known data errors
>    pool: tank
>   state: ONLINE
>   scrub: scrub in progress, 0.00% done, 231h16m to go
> config:
>
>          NAME        STATE     READ WRITE CKSUM
>          tank        ONLINE       0     0     0
>            ad6s2d    ONLINE       0     0     0
>
> errors: No known data errors
>    pool: tank
>   state: ONLINE
>   scrub: scrub in progress, 0.00% done, 283h55m to go
> config:
>
>          NAME        STATE     READ WRITE CKSUM
>          tank        ONLINE       0     0     0
>            ad6s2d    ONLINE       0     0     0
>
> errors: No known data errors
>    pool: tank
>   state: ONLINE
>   scrub: scrub in progress, 0.00% done, 232h8m to go
> config:
>
>          NAME        STATE     READ WRITE CKSUM
>          tank        ONLINE       0     0     0
>            ad6s2d    ONLINE       0     0     0
>
> errors: No known data errors
>    pool: tank
>   state: ONLINE
>   scrub: scrub in progress, 0.00% done, 164h37m to go
> config:
>
>          NAME        STATE     READ WRITE CKSUM
>          tank        ONLINE       0     0     0
>            ad6s2d    ONLINE       0     0     0
>
> errors: No known data errors
>    pool: tank
>   state: ONLINE
>   scrub: scrub in progress, 0.00% done, 183h40m to go
> config:
>
>          NAME        STATE     READ WRITE CKSUM
>          tank        ONLINE       0     0     0
>            ad6s2d    ONLINE       0     0     0
>
> errors: No known data errors
>    pool: tank
>   state: ONLINE
>   scrub: scrub in progress, 0.00% done, 166h21m to go
> config:
>
>          NAME        STATE     READ WRITE CKSUM
>          tank        ONLINE       0     0     0
>            ad6s2d    ONLINE       0     0     0
>
> errors: No known data errors
>    pool: tank
>   state: ONLINE
>   scrub: scrub stopped with 0 errors on Wed Nov 26 12:02:02 2008
> config:
>
>          NAME        STATE     READ WRITE CKSUM
>          tank        ONLINE       0     0     0
>            ad6s2d    ONLINE       0     0     0
> ****oops, scrub is reported as stopped****
>
> errors: No known data errors
>    pool: tank
>   state: ONLINE
>   scrub: scrub in progress, 0.00% done, 127h29m to go
> config:
>
>          NAME        STATE     READ WRITE CKSUM
>          tank        ONLINE       0     0     0
>            ad6s2d    ONLINE       0     0     0
>
> errors: No known data errors
>
Do you have a script or something that creates snapshots running?

I used sysutils/zfs-snapshot-mgmt and did see the same as you, as a running 
scrub is reset by a snapshot creation.

If you are using this script, we have tested a modified version that 
suspends snapshot creation on a pool that is scrubbing.

/glz


---
"There is hopeful symbolism in the fact that flags do not wave in a vacuum."
                -- Arthur C. Clarke