Re: [Gluster-devel] [Gluster-users] Geo Replication Hooks

[Fred van Zwieten]

Hey Venky,

That sounds...promising. But, I would like to do stuff *after* a file is changed on the source but *before* the change is pushed through a geo-repl link to a target. When multi fan-out replication is done, it should even be possible to have some custom stuff happening on one target and some other custom stuff on another target.\

Is that possible without touching the Geo-replication code? Then, I am *very* interested indeed.

Fred

On Tue, Nov 26, 2013 at 6:42 AM, Venky Shankar <address@hidden> wrote:

Hey Fred,

You could implement this without touching Geo-Replication code. Gluster now has the changelog translator (journaling mechanism) which records changes made to the filesystem (on each brick). Journals can be consumed using the changelog consumer library (libgfchangelog). Geo-Replication is just one such consumer of the changelogs (earlier the change detection mechanism used to be a filesystem crawl based on xtime).

Thinking from hook-scripts POV, you would even invoke them from libgfchangelog -- which gets notified by the changelog translator after a certain time interval. The granularity here would be a bunch of files (GFIDs actually, not file names) instead of per file basis. The library has APIs to mark changelogs as processed, which would be used to invoke post replication hooks (but this is only on source, not on destination).

Let me know what you think of the above approaches.

Thanks,

-venky

On Tue, Nov 26, 2013 at 3:13 AM, Fred van Zwieten <address@hidden> wrote:

Hi,

I have created a proposal for the implementation of Geo Replication Hooks. See here: http://www.gluster.org/community/documentation/index.php/Features/Geo_Replication_Hooks

Any comments, thoughts, etc would be great.

Fred

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