Re: File Size and Brick Size

ML Wong <wongmlb@xxxxxxxxx> · Thu, 29 Sep 2016 22:03:02 -0700

Hello Krutika, Ravishankar,Unfortunately, i deleted my previous test instance in AWS (running on EBS storage, on CentOS7 with XFS).
I was using 3.7.15 for Gluster.  It's good to know they should be the same. And, i have also set up another set of VMs quick locally, and use the same version of 3.7.15. It did return the same checksum. I will see if i have time and resources to set a test again in AWS.

Thank you both for the promptly reply,
Melvin

On Tue, Sep 27, 2016 at 7:59 PM, Krutika Dhananjay <kdhananj@xxxxxxxxxx> wrote:
Worked fine for me actually.

# md5sum lastlog 
ab7557d582484a068c3478e342069326  lastlog
# rsync -avH lastlog  /mnt/
sending incremental file list
lastlog

sent 364,001,522 bytes  received 35 bytes  48,533,540.93 bytes/sec
total size is 363,912,592  speedup is 1.00
# cd /mnt
# md5sum lastlog
ab7557d582484a068c3478e342069326  lastlog

-Krutika

On Wed, Sep 28, 2016 at 8:21 AM, Krutika Dhananjay <kdhananj@xxxxxxxxxx> wrote:
Hi,

What version of gluster are you using?
Also, could you share your volume configuration (`gluster volume info`)?

-Krutika

On Wed, Sep 28, 2016 at 6:58 AM, Ravishankar N <ravishankar@xxxxxxxxxx> wrote:

    On 09/28/2016 12:16 AM, ML Wong wrote:

      Hello Ravishankar,
        Thanks for introducing the sharding feature to me.
        It does seems to resolve the problem i was encountering
          earlier. But I have 1 question, do we expect the checksum of
          the file to be different if i copy from directory A to a
          shard-enabled volume?

    No the checksums must match. Perhaps Krutika who works on Sharding
    (CC'ed) can help you figure out why that isn't the case here.

    -Ravi

          [xxxxx@ip-172-31-1-72 ~]$ sudo sha1sum
            /var/tmp/oVirt-Live-4.0.4.iso
          ea8472f6408163fa9a315d878c651a519fc3f438
             /var/tmp/oVirt-Live-4.0.4.iso
          [xxxxx@ip-172-31-1-72 ~]$ sudo rsync -avH
            /var/tmp/oVirt-Live-4.0.4.iso /mnt/
          sending incremental file list
          oVirt-Live-4.0.4.iso

          sent 1373802342 bytes  received 31 bytes  30871963.44
            bytes/sec
          total size is 1373634560  speedup is 1.00
          [xxxxx@ip-172-31-1-72 ~]$ sudo sha1sum
            /mnt/oVirt-Live-4.0.4.iso
          14e9064857b40face90c91750d79c4d8665b9cab
             /mnt/oVirt-Live-4.0.4.iso

        On Mon, Sep 26, 2016 at 6:42 PM,
          Ravishankar N <ravishankar@xxxxxxxxxx>
          wrote:

                On 09/27/2016 05:15 AM, ML Wong wrote:

                  Have anyone in the list who has tried
                    copying file which is bigger than the individual
                    brick/replica size?
                    Test Scenario:
                    Distributed-Replicated volume, 2GB size, 2x2 =
                      4 bricks, 2 replicas
                    Each replica has 1GB

                    When i tried to copy file this volume, by both
                      fuse, or nfs mount. i get I/O error.

                      Filesystem                  Size  Used Avail
                        Use% Mounted on
                      /dev/mapper/vg0-brick1     1017M   33M  985M
                          4% /data/brick1
                      /dev/mapper/vg0-brick2     1017M  109M  909M
                         11% /data/brick2
                      lbre-cloud-dev1:/sharevol1  2.0G  141M  1.9G
                          7% /sharevol1

                      [xxxxxx@cloud-dev1 ~]$ du -sh
                        /var/tmp/ovirt-live-el7-3.6.2.iso 
                      1.3G	/var/tmp/ovirt-live-el7-3.6.2.iso

                      [melvinw@lbre-cloud-dev1 ~]$ sudo cp
                        /var/tmp/ovirt-live-el7-3.6.2.iso
                        /sharevol1/
                      cp: error writing
                        ‘/sharevol1/ovirt-live-el7-3.6.2.iso’:
                        Input/output error
                      cp: failed to extend
                        ‘/sharevol1/ovirt-live-el7-3.6.2.iso’:
                        Input/output error
                      cp: failed to close
                        ‘/sharevol1/ovirt-live-el7-3.6.2.iso’:
                        Input/output error

               Does the mount log give you more information? It
              it was a disk full issue, the error you would get is
              ENOSPC and not EIO. This looks like something else.

                    I know, we have experts in this mailing list.
                      And, i assume, this is a common situation where
                      many Gluster users may have encountered.  The
                      worry i have what if you have a big VM file
                      sitting on top of Gluster volume ...?

               It is recommended to use sharding (http://blog.gluster.org/2015/12/introducing-shard-translator/)
              for VM workloads to alleviate these kinds of issues.

              -Ravi

                    Any insights will be much appreciated.

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