Re: [Gluster-devel] Appending time to snap name in USS

Mohammed Rafi K C <rkavunga@xxxxxxxxxx> · Fri, 06 Feb 2015 10:58:23 +0530



    We decided to append time-stamp with snapname when creating a
    snapshot by default. Users can override this with a flag
    "no-timestamp", then snapshot will be created without appending
    time-stamp. So the snapshot create syntax would be like " snapshot
    create <snapname> <volname(s)> [no-timestamp] 
    [description <description>] [force] ".

    
    Patch for the same can be found here
    http://review.gluster.org/#/c/9597/1.

    
    Regards

    Rafi KC

    
    On 01/09/2015 12:18 PM, Poornima
      Gurusiddaiah wrote:

    
        Yes, the creation time of the snap is appended to the
          snapname dynamically, 
        i.e. snapview-server takes the snaplist from glusterd, and
          while populating the dentry for the ".snaps" it appends the
          time.

        
        Thanks,

        
        Poornima

        
        From:
          "Anand Avati" <avati@xxxxxxxxxxx>

          To: "Poornima Gurusiddaiah"
          <pgurusid@xxxxxxxxxx>, "Gluster Devel"
          <gluster-devel@xxxxxxxxxxx>, "gluster-users"
          <gluster-users@xxxxxxxxxxx>

          Sent: Friday, January 9, 2015 1:49:02 AM

          Subject: Re: [Gluster-devel] Appending time to snap
          name in USS

          
          It would be convenient if the time is appended to the snap
          name on the fly (when receiving list of snap names from
          glusterd?) so that the timezone application can be dynamic
          (which is what users would expect).

          
          Thanks
          

          On Thu Jan 08 2015 at 3:21:15 AM
            Poornima Gurusiddaiah <pgurusid@xxxxxxxxxx>
            wrote:

            
                  Hi,

                  
                  Windows has a feature called shadow copy. This is
                    widely used by all
                  windows users to view the previous versions of a
                    file.

                    For shadow copy to work with glusterfs backend, the
                    problem was that 
                  the clients expect snapshots to contain some
                    format

                    of time in their name.

                    
                    After evaluating the possible ways(asking the user
                    to create

                    snapshot with some format of time in it and have
                    rename snapshot

                    for existing snapshots) the following method seemed
                    simpler.

                    
                    If the USS is enabled, then the creation time of the
                    snapshot is

                    appended to the snapname and is listed in the .snaps
                    directory.

                    The actual name of the snapshot is left unmodified.
                    i.e. the  snapshot

                    list/info/restore etc. commands work with the
                    original snapname.
                  The patch for the same can be found @http://review.gluster.org/#/c/9371/

                  
                  The impact is that, the users would see the
                    snapnames to be different in the ".snaps" folder

                  
                  than what they have created. Also the current
                    patch does not take care of the scenario where

                  
                  the snapname already has time in its name.

                  
                    Eg:

                    Without this patch:

                    drwxr-xr-x 4 root root 110 Dec 26 04:14 snap1

                    drwxr-xr-x 4 root root 110 Dec 26 04:14 snap2

                    
                    With this patch

                    drwxr-xr-x 4 root root 110 Dec 26 04:14
                    snap1@GMT-2014.12.30-05.07.50

                    drwxr-xr-x 4 root root 110 Dec 26 04:14
                    snap2@GMT-2014.12.30-23.49.02
                    

                  Please let me know if you have any suggestions or
                    concerns on the same.

                  
                  Thanks,

                  
                  Poornima

                  
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