Where can one find reports of scrub activity?

[Charles Elliott]

Can someone tell me how I can find out if ZFS scrubbing activity is actually taking place? Is there or log or something?

 

[danb35]

Two ways. First, you can log into the shell (ssh in, or web shell, whichever you prefer) and run "zpool status". That will show the date and time the last scrub was completed. Second, log into the WebGUI, go to Storage, select your pool, and click on the status button at the bottom (it looks like a blank sheet of paper). That will show that a scrub has been completed, but not the date and time. You should also get an email when the scrub starts, if you've properly configured the email settings on your server (and if you haven't, you should).
Result of zpool status:

Status page in WebGUI:

 

[Charles Elliott]

Thank you very much for your prompt reply to my question.

My zpool status display does not show what yours does:

Code:

  pool: Mark
state: ONLINE
status: Some supported features are not enabled on the pool. The pool can
    still be used, but some features are unavailable.
action: Enable all features using 'zpool upgrade'. Once this is done,
    the pool may no longer be accessible by software that does not support
    the features. See zpool-features(7) for details.
  scan: resilvered 404M in 0h1m with 0 errors on Sat Aug 16 09:45:59 2014
config:
 
    NAME                                            STATE     READ WRITE CKSUM
    Mark                                            ONLINE       0     0     0
      raidz1-0                                      ONLINE       0     0     0
        gptid/71424a08-32c4-11e3-b166-002590a4fcaa  ONLINE       0     0     0
        gptid/71b48663-32c4-11e3-b166-002590a4fcaa  ONLINE       0     0     0
        gptid/72242371-32c4-11e3-b166-002590a4fcaa  ONLINE       0     0     0
    cache
      ada3                                          ONLINE       0     0     0
 
errors: No known data errors

Pls note that I have not enabled any new features, in part because I can not find anything like zpool-features(7) to determine what these new features might be, and in part because I am terrified of losing access to my data. If you know anything about this, that would help, too.

Below is an image of the FreesNAS WebGUI when "View ZFS scrubs" is clicked. Pls note that the word "status" does not appear anywhere on the page. Do you know anything about this?

 

[danb35]

The ZFS scrubs page isn't where you'd go to see if a scrub has completed; it's where you'd set the schedule. You'd go to the volume status page to see if a scrub had completed, but the output of zpool status shows that a scrub hasn't run, if at all, since before 16 August.

The scrub scheduling is a bit unintuitive. Yours is set to run at midnight on Sundays after at least 35 days have elapsed since the last scrub--which means it will run every six weeks. The schedule is up to you, but if you want it more frequently than that, you'll want to change the "threshold days" to a smaller number. I have mine set to 12 days, Sunday, at 22:00, which results in it happening every two weeks. If I set the "threshold days" to 14, I believe it would result in the scan running every three weeks--at 2200 on Sunday of the second week, it won't yet have been 14 full days since the last scrub completed. I hope this explanation helps; like I said, it can be a bit unintuitive.

On the pool version, it looks like you set up your pool under an older version of FreeNAS. This isn't a problem, but you'll probably want to do the zpool upgrade from the command line at some time. What version of FreeNAS are you running now?

 

[Charles Elliott]

Thanks for your help. I finally found the volume status page; it was just where you said it was. It reports "Scrub Status: none requested."

I originally installed version 9.1.1 of FreeNAS around 10/11/13. I then installed several updates finally ending with 9.2.1.7 between 8/8 and 8/16/14.

I changed the Threshold days to 12. We'll see what happens.

Thanks again.

 

[danb35]

http://forums.freenas.org/index.php?threads/checking-zpool-version.16922/#post-88458 will show you how to determine what version your pool is, and which feature flags it supports. This should not be a high-priority issue for you, though.

 

[Charles Elliott]

FreeNAS performed a scrub on Sunday morning at 1:00; here is the message "starting scrub of pool 'Mark'" and
"scrub repaired 128K in 1h45m with 0 errors on Sun Sep 7 02:45:18 2014." The scrub ran for 1:45:00. I have seen FreeNAS transfer files continuously at 600 Mbps. So 600 Mbps x 6300 seconds = 3,780,00 bits scrubbed = 472,500 bytes scrubbed. The NAS has 924.3 GiB in storage =
992,459,567,923 bytes. 472,500 * 100 / 992,459,567,923 = 0.00004761 % of the data scrubbed. What about the other 99.99995239% of the data?