[Bugs] [Bug 1369450] New: Timestamp difference on replica

[bugzilla at redhat.com]

https://bugzilla.redhat.com/show_bug.cgi?id=1369450

            Bug ID: 1369450
           Summary: Timestamp difference on replica
           Product: GlusterFS
           Version: 3.8.2
         Component: replicate
          Keywords: Triaged
          Severity: medium
          Priority: medium
          Assignee: bugs at gluster.org
          Reporter: hgowtham at redhat.com
                CC: atalur at redhat.com, bugs at gluster.org,
                    mselvaga at redhat.com, zsarosi at gmail.com
        Depends On: 1171048



+++ This bug was initially created as a clone of Bug #1171048 +++

Description of problem:
In a replication setup the same file has different timestamps (all three:
Access, Modify and Change differ) on the different nodes. The difference is
relatively small, in ms range and it is about the same as the difference of the
system-clocks. The underlying filesystem is ext4.


Version-Release number of selected component (if applicable):
tested on:
3.6.1
3.5.1
3.4.2


How reproducible:
always

Steps to Reproduce:
0. gluster volume is mounted through glusterfs-fuse on both replica node server
using their own hostname to /mnt (on node1: mount -t glusterfs node1:gv_share
/mnt; on node2: mount -t glusterfs node2:gv_share /mnt)
1. create file on node1, eg. node1# dd if=/dev/zero of=/mnt/testfile bs=1k
count=1
2. node1# stat /mnt/testfile
3. node2# stat /mnt/testfile

Actual results:
The 2 stat results differ with a couple of ms. After "touch"-ing the file, the
"modify" timestamp gets updated (rounded to integer s) and then it will be the
same on both nodes, however the "change" will be still different.


Expected results:
the 2 stat results should be the same on both nodes

Additional info:
I use ntp to synchronise the system clocks of the nodes but obviously there is
always some fluctuation in the ms range.
The differences in the timestams means a problem for IBM TSM backup client: if
the TSM client runs on both server and does an incremental backup to a common
TSM node. The 2 TSM clients from the two replica servers see different
timestamps and wants to update the file on the TSM server however it is the
same unchanged file it just has a different timestamp depending on the server
on which the TSM client runs.

--- Additional comment from Anuradha on 2016-06-15 05:18:18 EDT ---

Hi,

We have taken this requirement to be fixed in the upcoming releases.

Thanks,
Anuradha.


Referenced Bugs:

https://bugzilla.redhat.com/show_bug.cgi?id=1171048
[Bug 1171048] Timestamp difference on replica
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