Re: 3.7.13, index healing broken?

Dmitry Melekhov <dm@xxxxxxxxxx> · Wed, 13 Jul 2016 08:50:41 +0400



    13.07.2016 08:43, Pranith Kumar
      Karampuri пишет:

    
          On Wed, Jul 13, 2016 at 9:41 AM,
            Dmitry Melekhov <dm@xxxxxxxxxx> wrote:

            
                13.07.2016 07:46, Pranith Kumar Karampuri пишет:

                
                        On Tue, Jul 12, 2016 at
                          9:27 PM, Dmitry Melekhov <dm@xxxxxxxxxx>
                          wrote:

                          
                              12.07.2016 17:39, Pranith Kumar
                                Karampuri пишет:

                              
                                  Wow, what are the steps
                                    to recreate the problem?

                                  
                               just set file length to zero,
                              always reproducible.
                          
                          
                          Changing things on the brick i.e. not
                            from gluster volume mount is not something
                            you want to do. In the worst case(I have
                            seen this only once in the last 5 years
                            though) where you do this it can lead to
                            data loss also. So please be aware of it.

                          
                 Data replication with gluster is a way to avoid
                data loss, right? Or no? If not- why use gluster then?

                I though that gluster self-healing will heal or at least
                report missed files or files with wrong lenths- i.e.
                corruptions visible just by reading brick's directory,

                not comparing data as bit rot detection...

                If this is not a bug, then gluster is not what I
                expected :-(

              
            Yes Data replication with gluster is a way to avoid
              data loss. Changing files directly on the brick is similar
              to changing internal data structures of a disk filesystem.
              Or changing the internal files of a database. Things may
              stop working as you expect it to. All the hardwork done by
              the stack is nullified if you fiddle with the data on the
              brick directly. To put it succinctly you enter into the
              area of undefined behavior if you start fiddling with the
              data on the brick directly. Unless it is a documented
              behaviour I suggest you don't do it.

            
    Sorry, I'm talking not about direct data manipulation in bricks as
    way to use gluster, I'm talking about problems detection and
    recovery.

    As I already said- if I for some reason ( real case  can be only by
    accident ) will delete file this will not be detected by self-heal
    daemon, and, thus, will lead to lower replication level, i.e. lower
    failure tolerance. 

    
_______________________________________________
Gluster-users mailing list
Gluster-users@xxxxxxxxxxx
http://www.gluster.org/mailman/listinfo/gluster-users