[Gluster-users] heal-count vs heal-info and "continual heals"?

[Pranith Kumar Karampuri]

On 04/19/2016 12:41 PM, Krutika Dhananjay wrote:
>
>
> On Tue, Apr 19, 2016 at 5:30 AM, Lindsay Mathieson 
> <lindsay.mathieson at gmail.com <mailto:lindsay.mathieson at gmail.com>> wrote:
>
>     Is it possible to confirm the following understandings on my part?
>
>
>     - heal info shows the list of files with uncommitted writes across
>     the bricks that would need heals **if** a brick went down before
>     the write was committed.
>
>
> Yes and no. So heal-info reports both files that truly need heal and 
> those that are currently participating in an uncommitted transaction. 
> The latter entries are reported as "possible undergoing heal". I 
> believe we are going to drop the latter category of entries going 
> forward. IIUC Pranith is working on something that does that. But I 
> will let him confirm that.

Lindsay,
          Heal info must show all the files/dirs that require heal. At 
the moment there is a bug where it says 'possibly undergoing heal' even 
when the file doesn't need heal, for which we sent a fix 
http://review.gluster.org/13873, this is undergoing review and should be 
available in next releases. Once this is in, Your understanding is 
correct. Only thing to add is, the write may fail with either brick 
going down or any other error too like ENOSPACE etc.

Pranith

>
>       * additionally it lists files being healed if a heal is in process
>       * writes can be data and metadata.
>
>
>     - statics heal-count shows the count of files **actually needing
>     healing**
>
>
> This is correct for the most part. The only remote case where it will 
> not report pending heals when it is supposed to is if some entries 
> were marked "dirty" (indicated by the presence of their index under 
> .glusterfs/indices/dirty). So it only considers count of entries 
> needing heal in .glusterfs/indices/xattrop but not 
> .glusterfs/indices/dirty.
>
> For what it's worth, I realised that we don't really need to use locks 
> to examine whether files need heal or not if the entries are under 
> indices/xattrop. So if there is an entry under 
> .glusterfs/indices/xattrop, it means it definitely needs heal. Only 
> the entries under .glusterfs/indices/dirty need careful inspection. 
> This will significantly enhance heal-info response time. So I will
> work on getting this change in, maybe for the next .x release.

I think with Krutika's fix heal info will be super fast compared to what 
we have now. Please use heal info. If there are any bugs we will fix 
them, it handles all corner cases.

Pranith
>
> -Krutika
>
>
>
>
>
>
>     So its perfectly ok to see files being listed by heal info on a
>     busy cluster, so long as they aren't marked as a heal in progress.
>
>
>     thanks ,
>
>     -- 
>     Lindsay Mathieson
>
>
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