[Gluster-users] Bitrot strange behavior

[Sweta Anandpara]

Hi Cedric,

Any file is picked up for signing by the bitd process after the 
predetermined wait of 120 seconds. This default value is captured in the 
volume option 'features.expiry-time' and is configurable - in your case, 
it can be set to 0 or 1.

Point 2 is correct. A file corrupted before the bitrot signature is 
generated will not be successfully detected by the scrubber. That would 
require admin/manual intervention to explicitly heal the corrupted file.

-Sweta

On 04/16/2018 10:42 PM, Cedric Lemarchand wrote:
> Hello,
>
> I am playing around with the bitrot feature and have some questions:
>
> 1. when a file is created, the "trusted.bit-rot.signature” attribute
> seems only created approximatively 120 seconds after its creations
> (the cluster is idle and there is only one file living on it). Why ?
> Is there a way to make this attribute generated at the same time of
> the file creation ?
>
> 2. corrupting a file (adding a 0 locally on a brick) before the
> creation of the "trusted.bit-rot.signature” do not provide any
> warning: its signature is different than the 2 others copies on other
> bricks. Starting a scrub did not show up anything. I would think that
> Gluster compares signature between bricks for this particular use
> cases, but it seems the check is only local, so a file corrupted
> before it’s bitrot signature creation stay corrupted, and thus could
> be served to clients whith bad data ?
>
> Gluster 3.12.8 on Debian Stretch, bricks on ext4.
>
> Volume Name: vol1
> Type: Replicate
> Volume ID: 85ccfaf2-5793-46f2-bd20-3f823b0a2232
> Status: Started
> Snapshot Count: 0
> Number of Bricks: 1 x 3 = 3
> Transport-type: tcp
> Bricks:
> Brick1: gluster-01:/data/brick1
> Brick2: gluster-02:/data/brick2
> Brick3: gluster-03:/data/brick3
> Options Reconfigured:
> storage.build-pgfid: on
> performance.client-io-threads: off
> nfs.disable: on
> transport.address-family: inet
> features.bitrot: on
> features.scrub: Active
> features.scrub-throttle: aggressive
> features.scrub-freq: hourly
>
> Cheers,
>
> Cédric
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