= NetApp Scrubbing =

**Summary**: How to perform a scrub on a Netapp Filer. \\
**Date**: Around 2015 \\
**Refactor**: 7 March 2025: Checked links and formatting. \\
{{tag>netapp}}

What does scrubbing do? The RAID-level scrub finds and corrects parity and checksum errors as well as media errors. The continuous media scrub is to detect and correct media errors in order to minimize the chance of storage system disruption due to a media error while a storage system is in degraded or reconstruction mode. All the information you find below is about the RAID-level scrubbing.

= See Scrub Status =

<code>
filer01> aggr scrub status -v
aggr scrub: status of /aggr0/plex0/rg0 :
        Current scrub is 69% complete (suspended).
        Last full scrub completed: Sun Jul  1 06:24:45 CEST 2012

aggr scrub: status of /aggr0/plex0/rg1 :
        Scrub is not active.
        Last full scrub completed: Sun Jul 15 01:06:38 CEST 2012

aggr scrub: status of /aggr0/plex0/rg2 :
        Scrub is not active.
        Last full scrub completed: Sun Jul 22 02:08:20 CEST 2012

aggr scrub: status of /aggr0/plex0/rg3 :
        Current scrub is 64% complete (suspended).
        Last full scrub completed: Sun Jun 24 01:18:20 CEST 2012

aggr scrub: status of /aggr0/plex0/rg4 :
        Scrub is not active.
        Last full scrub completed: Sun Jul  8 03:24:46 CEST 2012

aggr scrub: status of /aggr1_SATA/plex0/rg0 :
        Current scrub is 4% complete (suspended).
        Last full scrub completed: Sun Jan  8 05:51:15 CET 2012

aggr scrub: status of /aggr1_SATA/plex0/rg1 :
        Current scrub is 20% complete (suspended).
        Last full scrub completed: Sun Jan  1 01:40:40 CET 2012

aggr scrub: status of /aggr2_SATA/plex0/rg0 :
        Scrub is not active.
        Last full scrub completed: Sun Aug 19 06:52:29 CEST 2012
</code>

= Resume a Scrub Process =

<code>
aggr scrub resume <aggr name / raid group name>
</code>

= Start a Scrub Process =

<code>
aggr scrub start <aggr name / raid group name>
</code>

= Suspend a Scrub Process =

<code>
aggr scrub suspend <aggr name / raid group name>
</code>

= Monitor Impact =

Check CPU and Kahuna, you need "priv set diag" mode to enable the option below:
<code>
filer01*> sysstat -M 1
ANY1+ ANY2+ ANY3+ ANY4+  AVG CPU0 CPU1 CPU2 CPU3 Network Protocol Cluster Storage Raid Target Kahuna WAFL_Ex(Kahu) WAFL_XClean SM_Exempt Cifs Exempt Intr Host  Ops/s   CP
  35%   14%    6%    2%  17%  17%  19%  18%  14%      1%       0%      0%      5%  10%     7%     3%     25%( 18%)          1%        0%   0%     5%   6%   4%   2547 100%
  68%   54%   43%   29%  51%  47%  50%  55%  50%      1%       0%      0%     11%  37%    11%     9%     80%( 52%)         21%        0%   0%    20%   8%   5%   4133 100%
  81%   48%   22%    6%  41%  37%  39%  49%  42%      1%       0%      0%     10%  31%    17%    14%     62%( 46%)          1%        0%   0%    16%   9%   5%   5663 100%
  69%   31%   10%    2%  31%  26%  31%  29%  36%      1%       0%      0%      6%  13%    19%    14%     49%( 39%)          0%        0%   0%     6%   9%   4%   6473 100%
  88%   56%   27%   10%  47%  33%  41%  47%  67%      1%       0%      0%      8%  23%    13%    32%     70%( 50%)         18%        0%   0%    12%   8%   5%   4481  99%
</code>

= Scrub Schedule =

By default, automatic disk scrubbing is enabled for once a week and begins at 1:00 a.m. on Sunday. By default the scrubbing is configured for 6 hours (360 minutes).  However, you can modify this schedule and/or the duration of the scrubbing to suit your needs:
<code>
filer01*> options raid.scrub
raid.scrub.duration          360
raid.scrub.enable            on
raid.scrub.perf_impact       low        (value might be overwritten in takeover)
raid.scrub.schedule
</code>

You can change the schedule by defining the option like this:
<code>
options raid.scrub.schedule 180m@sun@4,8h@mon@22
</code>
This sets two schedules:
* First: 180 minutes @ sunday @ 4:00 (AM)
* Second: 8 hours @ monday @ 22:00