[Gluster-devel] Object Quota feature proposal for GlusterFS-3.7

[Prashanth Pai]

Of the 3 options available for gfid to path conversions, "build-pgfid" is most efficient and convenient. However, it works only for newly created files after the option was turned on but not for existing files. There should be some external mechanism to populate the required xattrs for existing files. Even if it is somehow populated externally, we still have to do a getxattr (https://github.com/prashanthpai/sof-object-listing/blob/master/changelog/changes.py#L48) for every changed GFID to get file path.

Regards,
 -Prashanth Pai

----- Original Message -----
From: "Vijay Bellur" <vbellur at redhat.com>
To: "Prashanth Pai" <ppai at redhat.com>, "Aravinda" <avishwan at redhat.com>, "Kotresh Hiremath Ravishankar" <khiremat at redhat.com>
Cc: "Luis Pabon" <lpabon at redhat.com>, "gluster-devel at gluster.org >> Gluster Devel" <gluster-devel at gluster.org>
Sent: Tuesday, February 24, 2015 4:08:12 PM
Subject: Re: [Gluster-devel] Object Quota feature proposal for GlusterFS-3.7

On 02/24/2015 02:54 PM, Prashanth Pai wrote:
> Changelog logs GFID. Swift DBs need file path (acc/cont/obj format). Methods[1] to convert GFID to Path are not stable and also expensive. And there's no way to know which files were deleted even if we know GFID[2].

(Answering inline is always a better approach on MLs :))

Thanks, Prashanth. Aravinda and Kotresh are working on a set of changes 
that might make both problems easier to address. I suspect that we may 
need some variant of [2] to find a generic answer for the 2nd problem.

What aspects of the gfid to path conversion do you deem as unstable? I 
assume that support for hardlinks would not be of interest to most swift 
deployments?

Regards,
Vijay


>
> [1] https://github.com/gluster/glusterfs/blob/master/doc/debugging/gfid-to-path.md
> [2] http://review.gluster.org/8376
>
> Regards,
>   -Prashanth Pai
>
> ----- Original Message -----
> From: "Vijay Bellur" <vbellur at redhat.com>
> To: "Prashanth Pai" <ppai at redhat.com>, "Luis Pabon" <lpabon at redhat.com>
> Cc: "gluster-devel at gluster.org >> Gluster Devel" <gluster-devel at gluster.org>
> Sent: Tuesday, February 24, 2015 12:41:07 PM
> Subject: Re: [Gluster-devel] Object Quota feature proposal for GlusterFS-3.7
>
> On 02/24/2015 10:54 AM, Prashanth Pai wrote:
>> Hi Luis,
>>
>> Currently, even with storage policies, there is no mechanism to update the container DBs with details of files created/modified/deleted over filesystem interface.
>> Hence a GET on a container would list objects that may or may not exist on disk. Also the metadata of container (bytes and object count) could be outdated.
>> We need a mechanism to detect change in GlusterFS (have explored changelog and inotify, both not feasible) and then lazily update Swift DBs so that the container listing and metadata would eventually look right.
>>
>
> What were the problems encountered while trying to use changelog?
>
> Thanks,
> Vijay
>
>
>