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    Testing ZFS with XCP-ng

    Scheduled Pinned Locked Moved Development
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    • stormiS
      stormi Vates 🪐 XCP-ng Team @borzel
      last edited by

      @borzel It would be nice also to improve https://github.com/xcp-ng/xcp/wiki/ZFS-on-XCP-ng-7.5-and-later because I wrote it and I never used zfs!

      borzelB 1 Reply Last reply Reply Quote 0
      • E
        eexodus
        last edited by eexodus

        @stormi @borzel Thank you. I was able to create the zpool with those two extra commands. I then created a dataset and created a type=file and device-config:location SR. I realize ZFS is still a new feature, but is that the recommended way? I'm completely new to Xen so I am not familiar with creating SRs.

        [root@xcp-ng-miqfcsgc] depmod -a
[root@xcp-ng-miqfcsgc] modprobe zfs
[root@xcp-ng-miqfcsgc] zpool create -f tank /dev/sda
[root@xcp-ng-miqfcsgc] zfs create tank/sr
[root@xcp-ng-miqfcsgc] xe sr-create host-uuid=MY_UUID name-label=zfs-sr type=file other-config:o_direct=false device-config:location=/tank/sr/zfs-sr
        1 Reply Last reply Reply Quote 0
        • borzelB
          borzel XCP-ng Center Team
          last edited by

          @eexodus said in Testing ZFS with XCP-ng:

          zpool create -f tank /dev/sda

          If you have 4k disks (aka Advanced Format) use ashift=12

          zpool create -o ashift=12 -f tank /dev/sda

          I would say, for the first testing, please use:

          zfs set sync=disabled tank
zfs set compress=lz4 tank
zfs set atime=off tank

          pool/discs can be live monitored with

          zpool iostat -v 1
          A 1 Reply Last reply Reply Quote 3
          • A
            AllooTikeeChaat @borzel
            last edited by

            @borzel Not sure if this thread is the right place to ask .. but whats the min and recommended requirements to test ZFS ?

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

              Well, depends on the level of perfs you want to achieve. A lot of RAM is the key.

              borzelB 1 Reply Last reply Reply Quote 0
              • borzelB
                borzel XCP-ng Center Team @olivierlambert
                last edited by

                @olivierlambert said in Testing ZFS with XCP-ng:

                A lot of RAM is the key.

                And if you want more performance, add more RAM 🙂

                1 Reply Last reply Reply Quote 0
                • borzelB
                  borzel XCP-ng Center Team @stormi
                  last edited by

                  @stormi said in Testing ZFS with XCP-ng:

                  @borzel It would be nice also to improve https://github.com/xcp-ng/xcp/wiki/ZFS-on-XCP-ng-7.5-and-later because I wrote it and I never used zfs!

                  I have no write permissions 😐

                  stormiS 1 Reply Last reply Reply Quote 0
                  • borzelB
                    borzel XCP-ng Center Team
                    last edited by borzel

                    Good ressource with a lot of information, how to really use ZFS, build storages, tuning, etc.: https://www.zfsbuild.com 📰

                    B 1 Reply Last reply Reply Quote 0
                    • B
                      buzzzo @borzel
                      last edited by

                      Zfs is a local sr and imho does not add too much advantages vs classic ext sr

                      The real value of zfs is to use built in replication to remote zfs system.
                      Proxmox has built a very interesting solutions around it: async replication of vm on a another node.

                      I know xoa already offer a similar solution but is snapshot based and everyone knows the performance and size problem with this approach.

                      borzelB olivierlambertO 2 Replies Last reply Reply Quote 0
                      • borzelB
                        borzel XCP-ng Center Team @buzzzo
                        last edited by borzel

                        @buzzzo said in Testing ZFS with XCP-ng:

                        Zfs is a local sr and imho does not add too much advantages vs classic ext sr

                        meeeep 🙂

                        • ZFS uses (in standard configuration) half the RAM as read cache
                        • with sync=disabled your writes are faster (but synced to discs every 5 seconds; in one sequential batch - efficient use of slow spinning drives!)
                        • it has checksums from fs-layer down to the device
                        • it's awesome 😉

                        know xoa already offer a similar solution but is snapshot based and everyone knows the performance and size problem with this approach.

                        If we all had 48 hours a day and more people in the team, we could fully integrate ZFS into XCP-ng (with all bells and whistles). But for now we are happy to have the first step done - loose integrate ZFS to start using it and testing stability of the dom0 with ZFS in it.

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

                          @buzzzo Double meeeep 😆

                          On file level SR (ext, NFS, local ZFS, XOSAN), there is no space issue doing snapshots. Also, perfs are good even with snapshots if you don't have an asthmatic SR.

                          B 1 Reply Last reply Reply Quote 0
                          • B
                            buzzzo @olivierlambert
                            last edited by

                            @olivierlambert meeep!!! ☺

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

                              Meep meep!

                              1 Reply Last reply Reply Quote 1
                              • borzelB
                                borzel XCP-ng Center Team
                                last edited by borzel

                                I tested latest and greatest XO (5.24.1 from sources) with latest XCP-ng 7.5 (incl. xcp-ng-extra repo/ZFS). Backups do not work 😞

                                If the VDI is on a ext-SR, all is fine, backup working.
                                If the VDI is on a File-SR (ZFS based), the backup says "VDI_ERROR" or "VDI Chain to long". I will provide logfiles tomorrow if needed.

                                Setup of my File-SR:
                                xe sr-create host-uuid=<xxx> name-label=zfssr type=file other-config:o_direct=false device-config:location=/zfspool/zfssr

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

                                  VDI chain too long doesn't seems related. It means you have a VDI chain that's around 30 files.

                                  Can you provide the exact/detailed error log?

                                  1 Reply Last reply Reply Quote 0
                                  • borzelB
                                    borzel XCP-ng Center Team
                                    last edited by borzel

                                    0_1534286419566_560b7fad-965d-42bc-8f40-2eed276163b8-grafik.png

                                    1 Reply Last reply Reply Quote 0
                                    • borzelB
                                      borzel XCP-ng Center Team
                                      last edited by borzel

                                      I searched in xensource.log, SMlog and syslog, no related entries found 😞

                                      How can I increase the loglevel of XO?

                                      Here's the log output if I start this job again:

                                      Aug 15 01:10:35 ubuntu xo-server[616]: 2018-08-14T23:10:35.241Z xo:xapi Snapshotting VM pmg as [XO Backup test] pmg
Aug 15 01:10:36 ubuntu xo-server[616]: 2018-08-14T23:10:36.948Z xo:xapi exporting VDI pmg 0
Aug 15 01:10:41 ubuntu xo-server[616]: 2018-08-14T23:10:41.289Z xo:xapi Deleting VM [XO Backup test] pmg
Aug 15 01:10:41 ubuntu xo-server[616]: 2018-08-14T23:10:41.585Z xo:xapi Deleting VDI pmg 0

                                      It's nearly nothing...

                                      1 Reply Last reply Reply Quote 0
                                      • nraynaudN
                                        nraynaud XCP-ng Team
                                        last edited by

                                        @borzel > The error is often in the Settings->Logs panel in XO in this case

                                        borzelB 1 Reply Last reply Reply Quote 0
                                        • borzelB
                                          borzel XCP-ng Center Team @nraynaud
                                          last edited by

                                          @nraynaud no, it's as empty as it could be 😞

                                          1 Reply Last reply Reply Quote 0
                                          • borzelB
                                            borzel XCP-ng Center Team
                                            last edited by

                                            I found something in /var/log/xensource.log (used tail -f /var/log/xensource.log | grep -i 'error')

                                            Aug 14 23:19:10 hw xapi: [error|hw|63005 INET :::80|[XO] VDI Export R:3001f7e5aa17|vhd_tool_wrapper] vhd-tool failed, returning VDI_IO_ERROR
Aug 14 23:19:10 hw xapi: [error|hw|63005 INET :::80|[XO] VDI Export R:3001f7e5aa17|vhd_tool_wrapper] vhd-tool output: vhd-tool: internal error, uncaught exception:#012          Unix.Unix_error(Unix.EINVAL, "open", "/var/run/sr-mount/9fc67ea3-c9b3-5e62-ecc3-7d1debf81744/6781ab7b-c475-4d72-a7d0-b2aeca2e81e3.vhd")#012          Raised at file "src/core/lwt.ml", line 3008, characters 20-29#012          Called from file "src/unix/lwt_main.ml", line 42, characters 8-18#012          Called from file "src/impl.ml", line 811, characters 4-23#012          Called from file "src/cmdliner_term.ml", line 27, characters 19-24#012          Called from file "src/cmdliner.ml", line 27, characters 27-34#012          Called from file "src/cmdliner.ml", line 106, characters 32-39
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:315adbf2ec6c|backtrace] [XO] VDI Export R:3001f7e5aa17 failed with exception Server_error(VDI_IO_ERROR, [ Device I/O errors ])
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:315adbf2ec6c|backtrace] Raised Server_error(VDI_IO_ERROR, [ Device I/O errors ])
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:315adbf2ec6c|backtrace] 1/13 xapi @ hw Raised at file ocaml/xapi/vhd_tool_wrapper.ml, line 59
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:315adbf2ec6c|backtrace] 2/13 xapi @ hw Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 22
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:315adbf2ec6c|backtrace] 3/13 xapi @ hw Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 26
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:315adbf2ec6c|backtrace] 4/13 xapi @ hw Called from file ocaml/xapi/export_raw_vdi.ml, line 47
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:315adbf2ec6c|backtrace] 5/13 xapi @ hw Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 22
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:315adbf2ec6c|backtrace] 6/13 xapi @ hw Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 26
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:315adbf2ec6c|backtrace] 7/13 xapi @ hw Called from file ocaml/xapi/export_raw_vdi.ml, line 54
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:315adbf2ec6c|backtrace] 8/13 xapi @ hw Called from file ocaml/xapi/export_raw_vdi.ml, line 65
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:315adbf2ec6c|backtrace] 9/13 xapi @ hw Called from file ocaml/xapi/server_helpers.ml, line 73
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:315adbf2ec6c|backtrace] 10/13 xapi @ hw Called from file ocaml/xapi/server_helpers.ml, line 91
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:315adbf2ec6c|backtrace] 11/13 xapi @ hw Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 22
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:315adbf2ec6c|backtrace] 12/13 xapi @ hw Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 26
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:315adbf2ec6c|backtrace] 13/13 xapi @ hw Called from file lib/backtrace.ml, line 177
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:315adbf2ec6c|backtrace]
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:fc8d0f58f1be|backtrace] VDI.export_raw_vdi D:315adbf2ec6c failed with exception Server_error(VDI_IO_ERROR, [ Device I/O errors ])
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:fc8d0f58f1be|backtrace] Raised Server_error(VDI_IO_ERROR, [ Device I/O errors ])
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:fc8d0f58f1be|backtrace] 1/13 xapi @ hw Raised at file lib/debug.ml, line 187
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:fc8d0f58f1be|backtrace] 2/13 xapi @ hw Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 22
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:fc8d0f58f1be|backtrace] 3/13 xapi @ hw Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 26
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:fc8d0f58f1be|backtrace] 4/13 xapi @ hw Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 22
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:fc8d0f58f1be|backtrace] 5/13 xapi @ hw Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 26
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:fc8d0f58f1be|backtrace] 6/13 xapi @ hw Called from file ocaml/xapi/xapi_http.ml, line 185
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:fc8d0f58f1be|backtrace] 7/13 xapi @ hw Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 22
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:fc8d0f58f1be|backtrace] 8/13 xapi @ hw Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 26
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:fc8d0f58f1be|backtrace] 9/13 xapi @ hw Called from file ocaml/xapi/server_helpers.ml, line 73
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:fc8d0f58f1be|backtrace] 10/13 xapi @ hw Called from file ocaml/xapi/server_helpers.ml, line 91
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:fc8d0f58f1be|backtrace] 11/13 xapi @ hw Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 22
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:fc8d0f58f1be|backtrace] 12/13 xapi @ hw Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 26
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:fc8d0f58f1be|backtrace] 13/13 xapi @ hw Called from file lib/backtrace.ml, line 177
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80|VDI.export_raw_vdi D:fc8d0f58f1be|backtrace]
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80||backtrace] VDI.export_raw_vdi D:fc8d0f58f1be failed with exception Server_error(VDI_IO_ERROR, [ Device I/O errors ])
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80||backtrace] Raised Server_error(VDI_IO_ERROR, [ Device I/O errors ])
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80||backtrace] 1/1 xapi @ hw Raised at file (Thread 63005 has no backtrace table. Was with_backtraces called?, line 0
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80||backtrace]
Aug 14 23:19:11 hw xapi: [error|hw|63005 INET :::80||xapi] Unhandled Api_errors.Server_error(VDI_IO_ERROR, [ Device I/O errors ])
                                            nraynaudN 1 Reply Last reply Reply Quote 0
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