[Bugs] [Bug 1275173] geo-replication: [RFE] Geo-replication + Tiering

[bugzilla at redhat.com]

https://bugzilla.redhat.com/show_bug.cgi?id=1275173



--- Comment #32 from Vijay Bellur <vbellur at redhat.com> ---
COMMIT: http://review.gluster.org/12429 committed in release-3.7 by Venky
Shankar (vshankar at redhat.com) 
------
commit 2eafd8a5c7fbcc23395c6e0f9c654e96e056698b
Author: Saravanakumar Arumugam <sarumuga at redhat.com>
Date:   Wed Oct 14 11:49:49 2015 +0530

    geo-rep: Avoid cold tier bricks during ENTRY operation

    This is a series of patch which aims to fix geo-replication
    in a Tiering Volume.

    Problem:
    Consider, a file is placed in volume initially and then hot tier is
    attached. During any operation on the file, due to lookup a linkto
    file is created in hot tier.

    Now, any namespace operation carried out on the file is recorded in
    both cold and hot tier.
    There is a room for races when both changelogs are replayed.

    Solution:
    So, We are going to replay (namespace related)operations
    only in the hot tier.

    Why?
    a. If the file is directly placed in Hot tier , all fops will be
    recorded in HOT tier.
    b. If  the file is already present in Cold tier, and if any fop is
    carried out, it creates linkto file in Hot tier.
    Now, operations like UNLINK, RENAME are captured in Hot
    tier(by means of linkto file).

    This way, we can get both tier's operation in HOT tier itself.

    Now, once the file is demoted to COLD tier, any namespace operation
    carried out on the cold tier can be avoided as we directly RECORD
    the same in HOT tier.

    How?
    1. Check whether the brick is cold tier and skip ENTRY operation.
    2. Also, if it is cold tier brick, use Xsync(which is used during initial
run).
       This will help in getting all cold tier bricks changes using File System
crawl
       and helps in avoiding races with hot tier brick(which can happen
       if historychangelog used in cold tier brick).

    Dependent patches:
    1. http://review.gluster.org/12239
    2. http://review.gluster.org/12326

    Change-Id: I7692b1dbb8813a7e253451bca02f8f09a5782dde
    BUG: 1275173
    Signed-off-by: Saravanakumar Arumugam <sarumuga at redhat.com>
    Reviewed-on: http://review.gluster.org/12355
    Tested-by: NetBSD Build System <jenkins at build.gluster.org>
    Tested-by: Gluster Build System <jenkins at build.gluster.com>
    Reviewed-by: Aravinda VK <avishwan at redhat.com>
    (cherry picked from commit 6188b5fcebc56b3d8af1956beeec9988f3e8f268)
    Reviewed-on: http://review.gluster.org/12429
    Reviewed-by: Venky Shankar <vshankar at redhat.com>

-- 
You are receiving this mail because:
You are on the CC list for the bug.
You are the assignee for the bug.