8 Replies Latest reply on May 2, 2018 10:33 PM by ChandraSekhar195

    Quiesece snapshot creates two delta files

    lvaibhavt Hot Shot

      Hi All,

       

      If you take a snapshot of VM (with 1 HDD on it) ---- if you go to ESXi Command line (putty) and to the VM folder and do a ls -lthr *.vmdk

       

      You would only see 1 delta.vmdk (which is the snapshot file) ; Today I realized that when I take a quiesce snapshot and do a ls -lthr *.vmdk ; there are delta files that get created?

       

       

       

      Any suggestions why two delta files are getting created

       

       

      Thanks

      Vaibhav

        • 1. Re: Quiesece snapshot creates two delta files
          DavoudTeimouri Master
          vExpert

          YES.

          Delta disk files 

          .vmdk file to which the guest operating system can write. The delta disk represents the difference between the current state of the virtual disk and the state that existed at the time that the previous snapshot was taken. When you take a snapshot, the state of the virtual disk is preserved, which prevents the guest operating system from writing to it, and a delta or child disk is created.

          A delta disk has two files, including a descriptor file that is small and contains information about the virtual disk, such as geometry and child-parent relationship information, and a corresponding file that contains the raw data.

          • 2. Re: Quiesece snapshot creates two delta files
            lvaibhavt Hot Shot

            Hi Davoud,

             

            I think you misunderstood me ; I was referring to below pic

             

            When there is one HDD on VM and if I take a memory or non quiesce snapshot then there is only 1 delta file and only 1 vmdk (for delta)

             

            When I have taken a quiesce snapshot I have two delta files for one HDD

             

            pic.PNG

             

             

            Thanks

            Vaibhav

            • 3. Re: Quiesece snapshot creates two delta files
              a.p. Guru
              Community WarriorsUser ModeratorsvExpert

              How did you create the snapshot (manually, script, backup application, ...)?

              I saw this behavior with backup applications where a first snapshot was created for the VM itself (as expected), and a second snapshot was created due to the backup application's way (independent-nonpersistent) to mount the VM's virtual disk for the backup.

               

              André

              • 4. Re: Quiesece snapshot creates two delta files
                lvaibhavt Hot Shot

                Hi,

                 

                I created quiesce snapshot manually on VM . There is no backup software involved here as I am doing it on a lab

                 

                I am unable to understand why two delta files

                • 5. Re: Quiesece snapshot creates two delta files
                  RAJ_RAJ Expert
                  vExpert

                  Hi ,

                   

                  Please create a snapshot and delete that with Delete All option .

                  Uninstall and install the vmware tool to latest .

                  Try again and let me know if you face same issue .

                   

                   

                  Also please check there is hdd .vmdk file avaialbel on the folder of the VM by browsing or from CLI  which is not in use  . This HDd may be you have remove from VM but not selected delete option

                   

                  Please check

                   

                  Regards

                  Rajesh

                  RAJESH RADHAKRISHNAN
                  VCA -DCV/WM/Cloud,VCP 5 - DCV/DT/CLOUD, ,VCP6-DCV, EMCISA,EMCSA,MCTS,MCPS,BCFA
                  https://ae.linkedin.com/in/rajesh-radhakrishnan-76269335
                  Mark my post as "helpful" or "correct" if I've helped resolve or answered your query!
                  • 6. Re: Quiesece snapshot creates two delta files
                    continuum Guru
                    vExpertUser ModeratorsCommunity Warriors

                    Have a look at the vmware.log that describes the process.
                    I would expect to see that the guest gets stunned twice and in between the VSS actions are executed.

                    • 7. Re: Quiesece snapshot creates two delta files
                      Techie01 Hot Shot

                      The two delta files are typically created only for quisced snapshots ( for windows 2k8 and above for windows and latest Linux kernels also support this).

                      One of the delta file contains the normal delta information and the other file ( which is small in size) contains the application consistent information . The combination of both these delta files ensures that the snapshot taken is not just filesystem consistent but application consistent.

                       

                      For windows GOS this is typically achieved by the VSS service

                      • 8. Re: Quiesece snapshot creates two delta files
                        ChandraSekhar195 Novice

                        Hi,

                         

                        Is this a new change? earlier it used to be different. Whether quisced or not it had created only a single delta vmdk file.

                         

                        Could you please point to VMware article describing the change? Tried to find the KB article or release notes with information mentioned but could not.

                         

                        Thanks,

                        Chandra