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    Testing ZFS with XCP-ng

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    • E Offline
      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
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      • borzelB Offline
        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 Offline
          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 ?

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          • olivierlambertO Offline
            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 Offline
              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 Offline
                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 Offline
                  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 Offline
                    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 Offline
                      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.

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                      • olivierlambertO Offline
                        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 Offline
                          buzzzo @olivierlambert
                          last edited by

                          @olivierlambert meeep!!! ☺

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

                            Meep meep!

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

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

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                                  • borzelB Offline
                                    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...

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                                    • nraynaudN Offline
                                      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 Offline
                                        borzel XCP-ng Center Team @nraynaud
                                        last edited by

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

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

                                            I'll try to run some tests on my side.

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