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    XCP-ng 8.3 public alpha 🚀

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    • jhansenJ Offline
      jhansen @olivierlambert
      last edited by

      @olivierlambert

      Great relief, I was beginning to have doubts about myself 😨 😀

      olivierlambertO 1 Reply Last reply Reply Quote 0
      • olivierlambertO Offline
        olivierlambert Vates 🪐 Co-Founder CEO @jhansen
        last edited by

        @jhansen said in XCP-ng 8.3 public alpha 🚀:

        @olivierlambert

        Great relief, I was beginning to have doubts about myself 😨 😀

        So, it works but ONLY for snap taken during a backup, not a manual snapshot 🙂

        jhansenJ C 3 Replies Last reply Reply Quote 0
        • jhansenJ Offline
          jhansen @olivierlambert
          last edited by

          @olivierlambert
          I'm trying that this weekend.
          Thanks in advance.

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          • jhansenJ Offline
            jhansen @olivierlambert
            last edited by

            @olivierlambert
            Here as promised a test of the [NOBAK] function.

            About the SR:
            NVME Raid
            Size: 2.4 TB used of 5.5 TB total (2.9 TB allocated)

            About "SRV-Test" VM:
            0 "SRV-Test" "NVME Raid" 50GB /dev/xvda
            1 "[NOBAK] SRV-Test Drive" "NVME Raid" 1.5 TB /dev/xvdb

            Manual snapshot takes both drives and ignores the [NOBAK]
            Backup via Xo works, only the first drive is backed up.
            You can follow this under TASKS in the XO.
            Under "File Restore" in the XO there are no data for the second drive.

            So beautiful - so good. The idea would actually be to back up a server with very large drives partially.

            So I change my VM to the following:
            0 "SRV-Test" "NVME Raid" 50GB /dev/xvda
            1 "[NOBAK] SRV-Test Drive" "NVME Raid" 1.5 TB /dev/xvdb
            2 "[NOBAK] SRV-Test second test drive" NVME raid 2 TB /dev/xvdc

            My SR looks know:
            NVME Raid
            4.4 TB used of 5.5 TB total (4.9 TB allocated)

            Exactly the same result as the first test, both with the manual snapshot and with the XO backup.
            Actually, the manual snapshot should not work at all, because there is not enough space on the SR to include all the drives, but due to thin provisioning it works because the drives are almost empty.

            Now I'm filling the drives with data so I'm sure there isn't enough space on the SR for a full snapshot of all the data.

            As expected, I get the error message "The specified storage repository has insufficient space" when taking a manual snapshot Everything is understandable since the manual snapshot saves the entire VM and there is no space for the 3.5 TB snapshot on the SR.

            Now I make another backup with XO, which previously only backed up the 50 GB of the first drive.
            UPS ... After a few seconds, the error "SR_BACKEND_FAILURE_44(, There is insufficient space, )" and the backup was aborted.

            So, XO seems to first test whether a complete backup/snapshot can be created with all drives and then backs up the 50 GB of the first drive.
            In my opinion a bit suboptimal because it doesn't solve the problem to always have twice the space on the SR as you used, even if I only want to back up the system disk of a VM with a few GB, for example. 😢

            Conclusion of the test:
            A) Manual Snapshot with only part of drives ([NOBAK]), does not work.
            B) Backup with XO with only part of the drives ([NOBAK]), works, but only if there is enough space for a complete snapshot of the VM on the SR.

            Hope you can use with my little test for something. 😊

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            • olivierlambertO Offline
              olivierlambert Vates 🪐 Co-Founder CEO
              last edited by

              Do you mean that the VM snapshot space is computing with all disks despite we decided to ignore one? If that's the issue, then it's a XAPI bug/something that we should add in the first place 🙂

              jhansenJ 1 Reply Last reply Reply Quote 0
              • jhansenJ Offline
                jhansen @olivierlambert
                last edited by

                @olivierlambert
                Exactly, it looks like the snapshot of the entire VM is always calculated first. If there is enough space then only the selected drive is taken in the backup, if not the Backup is aborted.
                In other words, only if you can take a manual snapshot of the VM, XO's backup will then only backup the selected drive.
                It would be good if the backup only checked whether there was enough space for a snapshot of the selected drive.

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                • olivierlambertO Offline
                  olivierlambert Vates 🪐 Co-Founder CEO
                  last edited by

                  Okay so it's not on XO, but on XAPI then. @psafont and @BenjiReis I assume it's a basic check in VM.snapshot that's not doing the right computation since we can ignore disk 🙂

                  jhansenJ psafontP 2 Replies Last reply Reply Quote 0
                  • jhansenJ Offline
                    jhansen @olivierlambert
                    last edited by

                    @olivierlambert
                    Seems like that to me too. Let me know if you found a solution. I leave the test VM on my Xen server so that I can test again at any time.

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                    • psafontP Offline
                      psafont @olivierlambert
                      last edited by

                      @olivierlambert Snapshot is in essence a VDI clone, I don't see any checks being done before the filtering for ignored VDIs is done. And that is done pretty early on, not sure why there are operations affecting virtual block devices from ignored VDIs: https://github.com/xapi-project/xen-api/blob/master/ocaml/xapi/xapi_vm_clone.ml#L416

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                      • olivierlambertO Offline
                        olivierlambert Vates 🪐 Co-Founder CEO
                        last edited by

                        I will try to reproduce it locally with xe and keeping you posted, thanks!

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                        • olivierlambertO Offline
                          olivierlambert Vates 🪐 Co-Founder CEO
                          last edited by

                          Okay so it works with xe. I'll see with XO doing a backup now.

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                          • olivierlambertO Offline
                            olivierlambert Vates 🪐 Co-Founder CEO
                            last edited by olivierlambert

                            I can't reproduce the bug with XO. Here is my test setup @jhansen :

                            1x VM with 2 disks:

                            • 1x 10GiB disk on a SR with plenty of space
                            • 1x [NOBAK] 900GiB local LVM disk (thick) on a 1TiB SR (you can't snapshot the disk without SR disk space failure)

                            I did a delta backup with XO and it worked.

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                            • jhansenJ Offline
                              jhansen @olivierlambert
                              last edited by jhansen

                              @olivierlambert
                              I will make a retry of the test.
                              Is the drive empty or filled with data
                              If the disk are empty it works for me to.

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                              • jhansenJ Offline
                                jhansen @olivierlambert
                                last edited by

                                @olivierlambert
                                by the way: which version of XO are you using, not that I am using an older one and that the cause is there.
                                My drives are also local LVM so should be "Thick" too.

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                                • olivierlambertO Offline
                                  olivierlambert Vates 🪐 Co-Founder CEO
                                  last edited by

                                  XOA on latest

                                  jhansenJ 1 Reply Last reply Reply Quote 0
                                  • jhansenJ Offline
                                    jhansen @olivierlambert
                                    last edited by jhansen

                                    @olivierlambert
                                    Hello,
                                    I created a new SR and installed a new VM and
                                    installed a new XO.
                                    The last one was definitely the answer.
                                    It's working now, so as far as backup via XO goes.
                                    I tested everything extensively, with different VM, SR and different drive fill levels, all ok.
                                    A manual snapshot won't work, but that's what it is.
                                    My old XO installation, unfortunately I didn't write down the version, was from January. Also, when I reinstalled, I switched from stable to latest as you indicated.
                                    Unfortunately, I can't say whether the pure stable update or the change to latest was the solution.
                                    But the main thing is a happy ending. 😊
                                    Greetings Joerg

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                                    • lawrencesystemsL Offline
                                      lawrencesystems Ambassador
                                      last edited by

                                      I did some testing with the 8.3 and it all went smooth except for one thing. We did a backup of a VM on 8.3 and if we try and restore it to version 8.2 I get the error

                                      "IMPORT_INCOMPATIBLE_VERSION"
                                      

                                      which makes sense and it's just a lab system so nothing critical. Is there a way to bring it back to 8.2 or should I update the rest of my lab to 8.3? 🙂

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                                      • olivierlambertO Offline
                                        olivierlambert Vates 🪐 Co-Founder CEO
                                        last edited by

                                        What kind of backup? Delta should work (CR and warm migration too). Only basic backup with XVAs aren't able to be restored on an older version (like many things in XAPI world, it's only forward compatible)

                                        lawrencesystemsL 1 Reply Last reply Reply Quote 1
                                        • lawrencesystemsL Offline
                                          lawrencesystems Ambassador @olivierlambert
                                          last edited by

                                          @olivierlambert

                                          This was a full backup not a delta so that makes sense. I think I need more of my lab servers to be on 8.3 so I can do some more testing. I did not find any issues and nothing broke using it so I need to try harder. 😉

                                          stormiS 1 Reply Last reply Reply Quote 1
                                          • olivierlambertO Offline
                                            olivierlambert Vates 🪐 Co-Founder CEO
                                            last edited by

                                            Great 🙂 In general: go for delta backup. It's faster (by a decent margin) because XVA generation is not really optimized on XAPI side. Even if you compare a first delta (so a "full") vs an XVA, it might be 30 to 50% faster to generate.

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