ML
    • Recent
    • Categories
    • Tags
    • Popular
    • Users
    • Groups
    • Register
    • Login

    Unable to delete KVM snapshot

    IT Discussion
    kvm fedora 27 snapshots error
    6
    26
    7.9k
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • J
      JaredBusch @stacksofplates
      last edited by

      @stacksofplates said in Unable to delete KVM snapshot:

      Just as a side note, if the guest is running a database it's best to install the QEMU guest agent. Then pass --atomic when you do the snapshot. This will quiesce the file system and then unfreeze it when the snapshot is finished.

      Plex has some type of DB backing store, but not horribly worried about it for this one.

      1 Reply Last reply Reply Quote 0
      • E
        Emad R @JaredBusch
        last edited by Emad R

        @jaredbusch

        Hi,

        What is the reasoning for doing external snapshots and going against the default (where everything is saved in one file), I use virt but I love virt-manager and with that it always does the snap internally.

        Any benefits of external aside being the ESXi way?

        Cause it seems here that what is causing the issue, and I recall somewhere I read the qcow2 expects everything to be in 1 file.

        I just read @stacksofplates basically what he says.

        J 1 Reply Last reply Reply Quote 0
        • J
          JaredBusch @Emad R
          last edited by

          @emad-r said in Unable to delete KVM snapshot:

          @jaredbusch

          Hi,

          What is the reasoning for doing external snapshots and going against the default (where everything is saved in one file), I use virt but I love virt-manager and with that it always does the snap internally.

          Any benefits of external aside being the ESXi way?

          Cause it seems here that what is causing the issue, and I recall somewhere I read the qcow2 expects everything to be in 1 file.

          I just read @stacksofplates basically what he says.

          because you cannot copy the file off to backup when you use the internal snapshot

          E S 2 Replies Last reply Reply Quote 2
          • J
            JaredBusch @stacksofplates
            last edited by

            @stacksofplates said in Unable to delete KVM snapshot:

            The type of snapshot you created is an external snapshot. The type that you create when you use the Virt-Manager gui is an internal. The internal all exist in the .qcow2 image and are copy on write. The external are AOW/ROW so they have to be block committed to the original backing store before you can delet them since all new writes/reads have been directed to the new image.

            I did external on purpose.

            I tested this on a smaller VM weeks ago and did not have a problem. I guess because nothing changed? I just made the snapshot and then deleted.

            1 Reply Last reply Reply Quote 0
            • J
              JaredBusch @stacksofplates
              last edited by

              @stacksofplates said in Unable to delete KVM snapshot:

              @dafyre said in Unable to delete KVM snapshot:

              Note, in the process below, <diskname> could be vda, sda, or hda.
              The first command tells you which to use.

              virsh domblklist plex
              virsh blockcommit plex <disk name> --verbose --pivot --active
              

              Once the blockcommit command finishes, shutdown plex, and rename the plex_snap disk image.

              Start Plex back up and make sure your updates and such are still installed. If all is well, then delete the plex_snap disk image.

              You shouldn’t have to shutdown the image unless it’s just for the updates. The pivot option points the guest back to the original backing store.

              But I still need to delete the backup file manually from disk?

              S 1 Reply Last reply Reply Quote 0
              • J
                JaredBusch @black3dynamite
                last edited by

                @black3dynamite said in Unable to delete KVM snapshot:

                Are you trying to delete the snapshot while the VM is still running?

                Of course.

                1 Reply Last reply Reply Quote 0
                • J
                  JaredBusch
                  last edited by

                  sudo virsh domblklist plex
                  Target     Source
                  ------------------------------------------------
                  hda        -
                  hdb        /kvm_store/disk_b/plex.plex_snap
                  
                  [jbusch@kvm ~]$ sudo virsh blockcommit plex hdb --verbose --pivot --active
                  Block commit: [ 26 %]
                  
                  1 Reply Last reply Reply Quote 0
                  • E
                    Emad R @JaredBusch
                    last edited by

                    @jaredbusch said in Unable to delete KVM snapshot:

                    @emad-r said in Unable to delete KVM snapshot:

                    @jaredbusch

                    Hi,

                    What is the reasoning for doing external snapshots and going against the default (where everything is saved in one file), I use virt but I love virt-manager and with that it always does the snap internally.

                    Any benefits of external aside being the ESXi way?

                    Cause it seems here that what is causing the issue, and I recall somewhere I read the qcow2 expects everything to be in 1 file.

                    I just read @stacksofplates basically what he says.

                    because you cannot copy the file off to backup when you use the internal snapshot

                    Interesting I dont take VM backup frequently, when I do I rsync the whole VM file.

                    rsync --progress --inplace -h -W /var/lib/libvirt/images/VM/centos7.0-clone.qcow2 root@192.168.1.22:/var/lib/libvirt/images/VM/centos7.0-clone.qcow2

                    This after the initial copy, if you are extra paranoid you can take the file everytime if you dont trust rsync algorithms.

                    But it is interesting this external snapshot approach, how much are the sizes of external snapshots roughly ? I know it depends but what are we dealing with here. 100 MB ?

                    S 1 Reply Last reply Reply Quote 0
                    • S
                      stacksofplates @JaredBusch
                      last edited by

                      @jaredbusch said in Unable to delete KVM snapshot:

                      @stacksofplates said in Unable to delete KVM snapshot:

                      @dafyre said in Unable to delete KVM snapshot:

                      Note, in the process below, <diskname> could be vda, sda, or hda.
                      The first command tells you which to use.

                      virsh domblklist plex
                      virsh blockcommit plex <disk name> --verbose --pivot --active
                      

                      Once the blockcommit command finishes, shutdown plex, and rename the plex_snap disk image.

                      Start Plex back up and make sure your updates and such are still installed. If all is well, then delete the plex_snap disk image.

                      You shouldn’t have to shutdown the image unless it’s just for the updates. The pivot option points the guest back to the original backing store.

                      But I still need to delete the backup file manually from disk?

                      Yes

                      1 Reply Last reply Reply Quote 0
                      • S
                        stacksofplates @JaredBusch
                        last edited by

                        @jaredbusch said in Unable to delete KVM snapshot:

                        @emad-r said in Unable to delete KVM snapshot:

                        @jaredbusch

                        Hi,

                        What is the reasoning for doing external snapshots and going against the default (where everything is saved in one file), I use virt but I love virt-manager and with that it always does the snap internally.

                        Any benefits of external aside being the ESXi way?

                        Cause it seems here that what is causing the issue, and I recall somewhere I read the qcow2 expects everything to be in 1 file.

                        I just read @stacksofplates basically what he says.

                        because you cannot copy the file off to backup when you use the internal snapshot

                        Allocate on Write snapshots are also much faster. It’s the way @scale does their snapshots. You can have thousands before you get a performance hit vs only a few with COW.

                        1 Reply Last reply Reply Quote 0
                        • S
                          stacksofplates @Emad R
                          last edited by

                          @emad-r said in Unable to delete KVM snapshot:

                          @jaredbusch said in Unable to delete KVM snapshot:

                          @emad-r said in Unable to delete KVM snapshot:

                          @jaredbusch

                          Hi,

                          What is the reasoning for doing external snapshots and going against the default (where everything is saved in one file), I use virt but I love virt-manager and with that it always does the snap internally.

                          Any benefits of external aside being the ESXi way?

                          Cause it seems here that what is causing the issue, and I recall somewhere I read the qcow2 expects everything to be in 1 file.

                          I just read @stacksofplates basically what he says.

                          because you cannot copy the file off to backup when you use the internal snapshot

                          Interesting I dont take VM backup frequently, when I do I rsync the whole VM file.

                          rsync --progress --inplace -h -W /var/lib/libvirt/images/VM/centos7.0-clone.qcow2 root@192.168.1.22:/var/lib/libvirt/images/VM/centos7.0-clone.qcow2

                          This after the initial copy, if you are extra paranoid you can take the file everytime if you dont trust rsync algorithms.

                          But it is interesting this external snapshot approach, how much are the sizes of external snapshots roughly ? I know it depends but what are we dealing with here. 100 MB ?

                          You have to shut the VM off to just rsync the drive. This way you can leave the VM on.

                          You don’t copy the external snapshot. You take a snapshot and copy the backing store. Then blockcommit (merge) the snapshot back into the original image.

                          E 1 Reply Last reply Reply Quote 0
                          • E
                            Emad R @stacksofplates
                            last edited by

                            @stacksofplates said in Unable to delete KVM snapshot:

                            @emad-r said in Unable to delete KVM snapshot:

                            @jaredbusch said in Unable to delete KVM snapshot:

                            @emad-r said in Unable to delete KVM snapshot:

                            @jaredbusch

                            Hi,

                            What is the reasoning for doing external snapshots and going against the default (where everything is saved in one file), I use virt but I love virt-manager and with that it always does the snap internally.

                            Any benefits of external aside being the ESXi way?

                            Cause it seems here that what is causing the issue, and I recall somewhere I read the qcow2 expects everything to be in 1 file.

                            I just read @stacksofplates basically what he says.

                            because you cannot copy the file off to backup when you use the internal snapshot

                            Interesting I dont take VM backup frequently, when I do I rsync the whole VM file.

                            rsync --progress --inplace -h -W /var/lib/libvirt/images/VM/centos7.0-clone.qcow2 root@192.168.1.22:/var/lib/libvirt/images/VM/centos7.0-clone.qcow2

                            This after the initial copy, if you are extra paranoid you can take the file everytime if you dont trust rsync algorithms.

                            But it is interesting this external snapshot approach, how much are the sizes of external snapshots roughly ? I know it depends but what are we dealing with here. 100 MB ?

                            You have to shut the VM off to just rsync the drive. This way you can leave the VM on.

                            You don’t copy the external snapshot. You take a snapshot and copy the backing store. Then blockcommit (merge) the snapshot back into the original image.

                            No need if you freeze the filesystem first then rsync. but for this I recommend taking each time the whole file with rsync

                            S 1 Reply Last reply Reply Quote 0
                            • dafyreD
                              dafyre @stacksofplates
                              last edited by

                              @stacksofplates said in Unable to delete KVM snapshot:

                              @dafyre said in Unable to delete KVM snapshot:

                              Note, in the process below, <diskname> could be vda, sda, or hda.
                              The first command tells you which to use.

                              virsh domblklist plex
                              virsh blockcommit plex <disk name> --verbose --pivot --active
                              

                              Once the blockcommit command finishes, shutdown plex, and rename the plex_snap disk image.

                              Start Plex back up and make sure your updates and such are still installed. If all is well, then delete the plex_snap disk image.

                              You shouldn’t have to shutdown the image unless it’s just for the updates. The pivot option points the guest back to the original backing store.

                              I do this because I've deleted the snapshot file after running blockcommit and had issues, so now I do that as a just in case measure. If it was something in production, I'd just leave the old snapshot file until the next maintenance window.

                              1 Reply Last reply Reply Quote 0
                              • S
                                stacksofplates @Emad R
                                last edited by

                                @emad-r said in Unable to delete KVM snapshot:

                                @stacksofplates said in Unable to delete KVM snapshot:

                                @emad-r said in Unable to delete KVM snapshot:

                                @jaredbusch said in Unable to delete KVM snapshot:

                                @emad-r said in Unable to delete KVM snapshot:

                                @jaredbusch

                                Hi,

                                What is the reasoning for doing external snapshots and going against the default (where everything is saved in one file), I use virt but I love virt-manager and with that it always does the snap internally.

                                Any benefits of external aside being the ESXi way?

                                Cause it seems here that what is causing the issue, and I recall somewhere I read the qcow2 expects everything to be in 1 file.

                                I just read @stacksofplates basically what he says.

                                because you cannot copy the file off to backup when you use the internal snapshot

                                Interesting I dont take VM backup frequently, when I do I rsync the whole VM file.

                                rsync --progress --inplace -h -W /var/lib/libvirt/images/VM/centos7.0-clone.qcow2 root@192.168.1.22:/var/lib/libvirt/images/VM/centos7.0-clone.qcow2

                                This after the initial copy, if you are extra paranoid you can take the file everytime if you dont trust rsync algorithms.

                                But it is interesting this external snapshot approach, how much are the sizes of external snapshots roughly ? I know it depends but what are we dealing with here. 100 MB ?

                                You have to shut the VM off to just rsync the drive. This way you can leave the VM on.

                                You don’t copy the external snapshot. You take a snapshot and copy the backing store. Then blockcommit (merge) the snapshot back into the original image.

                                No need if you freeze the filesystem first then rsync. but for this I recommend taking each time the whole file with rsync

                                Uh there’s no difference. If you freeze the system it can’t be used. This is to run on live systems so they remain running the whole time.

                                J E 2 Replies Last reply Reply Quote 1
                                • J
                                  JaredBusch @stacksofplates
                                  last edited by

                                  @stacksofplates said in Unable to delete KVM snapshot:

                                  @emad-r said in Unable to delete KVM snapshot:

                                  @stacksofplates said in Unable to delete KVM snapshot:

                                  @emad-r said in Unable to delete KVM snapshot:

                                  @jaredbusch said in Unable to delete KVM snapshot:

                                  @emad-r said in Unable to delete KVM snapshot:

                                  @jaredbusch

                                  Hi,

                                  What is the reasoning for doing external snapshots and going against the default (where everything is saved in one file), I use virt but I love virt-manager and with that it always does the snap internally.

                                  Any benefits of external aside being the ESXi way?

                                  Cause it seems here that what is causing the issue, and I recall somewhere I read the qcow2 expects everything to be in 1 file.

                                  I just read @stacksofplates basically what he says.

                                  because you cannot copy the file off to backup when you use the internal snapshot

                                  Interesting I dont take VM backup frequently, when I do I rsync the whole VM file.

                                  rsync --progress --inplace -h -W /var/lib/libvirt/images/VM/centos7.0-clone.qcow2 root@192.168.1.22:/var/lib/libvirt/images/VM/centos7.0-clone.qcow2

                                  This after the initial copy, if you are extra paranoid you can take the file everytime if you dont trust rsync algorithms.

                                  But it is interesting this external snapshot approach, how much are the sizes of external snapshots roughly ? I know it depends but what are we dealing with here. 100 MB ?

                                  You have to shut the VM off to just rsync the drive. This way you can leave the VM on.

                                  You don’t copy the external snapshot. You take a snapshot and copy the backing store. Then blockcommit (merge) the snapshot back into the original image.

                                  No need if you freeze the filesystem first then rsync. but for this I recommend taking each time the whole file with rsync

                                  Uh there’s no difference. If you freeze the system it can’t be used. This is to run on live systems so they remain running the whole time.

                                  I guess I need to look into your backup script thing one of these days.

                                  The systems I want to backup are not stateful, like yours, but it will give me a starting point.

                                  S 1 Reply Last reply Reply Quote 0
                                  • S
                                    stacksofplates @JaredBusch
                                    last edited by

                                    @jaredbusch said in Unable to delete KVM snapshot:

                                    @stacksofplates said in Unable to delete KVM snapshot:

                                    @emad-r said in Unable to delete KVM snapshot:

                                    @stacksofplates said in Unable to delete KVM snapshot:

                                    @emad-r said in Unable to delete KVM snapshot:

                                    @jaredbusch said in Unable to delete KVM snapshot:

                                    @emad-r said in Unable to delete KVM snapshot:

                                    @jaredbusch

                                    Hi,

                                    What is the reasoning for doing external snapshots and going against the default (where everything is saved in one file), I use virt but I love virt-manager and with that it always does the snap internally.

                                    Any benefits of external aside being the ESXi way?

                                    Cause it seems here that what is causing the issue, and I recall somewhere I read the qcow2 expects everything to be in 1 file.

                                    I just read @stacksofplates basically what he says.

                                    because you cannot copy the file off to backup when you use the internal snapshot

                                    Interesting I dont take VM backup frequently, when I do I rsync the whole VM file.

                                    rsync --progress --inplace -h -W /var/lib/libvirt/images/VM/centos7.0-clone.qcow2 root@192.168.1.22:/var/lib/libvirt/images/VM/centos7.0-clone.qcow2

                                    This after the initial copy, if you are extra paranoid you can take the file everytime if you dont trust rsync algorithms.

                                    But it is interesting this external snapshot approach, how much are the sizes of external snapshots roughly ? I know it depends but what are we dealing with here. 100 MB ?

                                    You have to shut the VM off to just rsync the drive. This way you can leave the VM on.

                                    You don’t copy the external snapshot. You take a snapshot and copy the backing store. Then blockcommit (merge) the snapshot back into the original image.

                                    No need if you freeze the filesystem first then rsync. but for this I recommend taking each time the whole file with rsync

                                    Uh there’s no difference. If you freeze the system it can’t be used. This is to run on live systems so they remain running the whole time.

                                    I guess I need to look into your backup script thing one of these days.

                                    The systems I want to backup are not stateful, like yours, but it will give me a starting point.

                                    It's pretty much what you did here with some other crap, like an interactive part. I should probably add more logic to it, it was just a quick thing I put together. I also mostly just backed up the data volumes. The OS 99% of the time is a separate disk from the data so I just back up the data.

                                    J 1 Reply Last reply Reply Quote 2
                                    • J
                                      JaredBusch @stacksofplates
                                      last edited by JaredBusch

                                      @stacksofplates said in Unable to delete KVM snapshot:

                                      @jaredbusch said in Unable to delete KVM snapshot:

                                      @stacksofplates said in Unable to delete KVM snapshot:

                                      @emad-r said in Unable to delete KVM snapshot:

                                      @stacksofplates said in Unable to delete KVM snapshot:

                                      @emad-r said in Unable to delete KVM snapshot:

                                      @jaredbusch said in Unable to delete KVM snapshot:

                                      @emad-r said in Unable to delete KVM snapshot:

                                      @jaredbusch

                                      Hi,

                                      What is the reasoning for doing external snapshots and going against the default (where everything is saved in one file), I use virt but I love virt-manager and with that it always does the snap internally.

                                      Any benefits of external aside being the ESXi way?

                                      Cause it seems here that what is causing the issue, and I recall somewhere I read the qcow2 expects everything to be in 1 file.

                                      I just read @stacksofplates basically what he says.

                                      because you cannot copy the file off to backup when you use the internal snapshot

                                      Interesting I dont take VM backup frequently, when I do I rsync the whole VM file.

                                      rsync --progress --inplace -h -W /var/lib/libvirt/images/VM/centos7.0-clone.qcow2 root@192.168.1.22:/var/lib/libvirt/images/VM/centos7.0-clone.qcow2

                                      This after the initial copy, if you are extra paranoid you can take the file everytime if you dont trust rsync algorithms.

                                      But it is interesting this external snapshot approach, how much are the sizes of external snapshots roughly ? I know it depends but what are we dealing with here. 100 MB ?

                                      You have to shut the VM off to just rsync the drive. This way you can leave the VM on.

                                      You don’t copy the external snapshot. You take a snapshot and copy the backing store. Then blockcommit (merge) the snapshot back into the original image.

                                      No need if you freeze the filesystem first then rsync. but for this I recommend taking each time the whole file with rsync

                                      Uh there’s no difference. If you freeze the system it can’t be used. This is to run on live systems so they remain running the whole time.

                                      I guess I need to look into your backup script thing one of these days.

                                      The systems I want to backup are not stateful, like yours, but it will give me a starting point.

                                      It's pretty much what you did here with some other crap, like an interactive part. I should probably add more logic to it, it was just a quick thing I put together. I also mostly just backed up the data volumes. The OS 99% of the time is a separate disk from the data so I just back up the data.

                                      Well, I also need a NAS to store things on until I can upload them too so I should work on that...

                                      1 Reply Last reply Reply Quote 0
                                      • E
                                        Emad R @stacksofplates
                                        last edited by

                                        @stacksofplates said in Unable to delete KVM snapshot:

                                        Uh there’s no difference. If you freeze the system it can’t be used. This is to run on live systems so they remain running the whole time.

                                        What no coffee break for servers !!!

                                        scottalanmillerS 1 Reply Last reply Reply Quote 0
                                        • scottalanmillerS
                                          scottalanmiller @Emad R
                                          last edited by

                                          @emad-r said in Unable to delete KVM snapshot:

                                          @stacksofplates said in Unable to delete KVM snapshot:

                                          Uh there’s no difference. If you freeze the system it can’t be used. This is to run on live systems so they remain running the whole time.

                                          What no coffee break for servers !!!

                                          They definitely get a break if you pour coffee on them.

                                          1 Reply Last reply Reply Quote 4
                                          • 1
                                          • 2
                                          • 1 / 2
                                          • First post
                                            Last post