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    How to Re-attach an SR

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    • C Offline
      Chrome @tjkreidl
      last edited by

      @tjkreidl Ok....I figured out how to get the uuid...

      I used this command:

      xe sr-introduce uuid=ONK72A-tDcE-rfAs-P78e-3hlk-wSE5-OVmyiL shared=true type=LVM2_member name-label=LocalSR
      

      Response:

      ONK72A-tDcE-rfAs-P78e-3hlk-wSE5-OVmyiL
      

      Which I figured was good:

      Then:

      xe sr-list
      

      Returns:

      uuid ( RO)                : a08b6338-3855-1da2-b108-ad9c5b553001
                name-label ( RW): Removable storage
          name-description ( RW): 
                      host ( RO): vm
                      type ( RO): udev
              content-type ( RO): disk
      
      
      uuid ( RO)                : ONK72A-tDcE-rfAs-P78e-3hlk-wSE5-OVmyiL
                name-label ( RW): LocalSR
          name-description ( RW): 
                      host ( RO): <not in database>
                      type ( RO): lvm2_member
              content-type ( RO): 
      
      
      uuid ( RO)                : dd4907eb-707d-1f1a-ee05-5ea838bca63a
                name-label ( RW): XCP-ng Tools
          name-description ( RW): XCP-ng Tools ISOs
                      host ( RO): vm
                      type ( RO): iso
              content-type ( RO): iso
      
      
      uuid ( RO)                : 84f169c5-4c4f-455a-ae1a-7629e9ce0b85
                name-label ( RW): DVD drives
          name-description ( RW): Physical DVD drives
                      host ( RO): vm
                      type ( RO): udev
              content-type ( RO): iso
      

      So, it looks like the SR was added back?

      tjkreidlT 1 Reply Last reply Reply Quote 0
      • tjkreidlT Offline
        tjkreidl Ambassador @Chrome
        last edited by tjkreidl

        @Chrome Try "xe vm-list params=all"
        Do you only have a local storage or did you have any attached storage that's not showing up?

        C 1 Reply Last reply Reply Quote 1
        • C Offline
          Chrome @tjkreidl
          last edited by

          @tjkreidl

          Here's the output:

          xe vm-list params=all
          uuid ( RO)                                  : 6dccd15c-2682-460c-9049-bdd210288c74
                                      name-label ( RW): Control domain on host: vm
                                name-description ( RW): The domain which manages physical devices and manages other domains
                                    user-version ( RW): 1
                                   is-a-template ( RW): false
                             is-default-template ( RW): false
                                   is-a-snapshot ( RO): false
                                     snapshot-of ( RO): <not in database>
                                       snapshots ( RO): 
                                   snapshot-time ( RO): 19700101T00:00:00Z
                                   snapshot-info ( RO): 
                                          parent ( RO): <not in database>
                                        children ( RO): 
                               is-control-domain ( RO): true
                                     power-state ( RO): running
                                   memory-actual ( RO): 8589934592
                                   memory-target ( RO): <expensive field>
                                 memory-overhead ( RO): 84934656
                               memory-static-max ( RW): 8589934592
                              memory-dynamic-max ( RW): 8589934592
                              memory-dynamic-min ( RW): 8589934592
                               memory-static-min ( RW): 8589934592
                                suspend-VDI-uuid ( RW): <not in database>
                                 suspend-SR-uuid ( RW): <not in database>
                                    VCPUs-params (MRW): 
                                       VCPUs-max ( RW): 16
                                VCPUs-at-startup ( RW): 16
                          actions-after-shutdown ( RW): Destroy
                        actions-after-softreboot ( RW): Soft reboot
                            actions-after-reboot ( RW): Destroy
                             actions-after-crash ( RW): Destroy
                                   console-uuids (SRO): ab3d576c-6b9d-8829-f4c1-c67d9873b03b; 030565eb-6b01-d076-81e8-3e2186eb79e9
                                             hvm ( RO): false
                                        platform (MRW): 
                              allowed-operations (SRO): metadata_export; changing_static_range; changing_dynamic_range
                              current-operations (SRO): 
                              blocked-operations (MRW): 
                             allowed-VBD-devices (SRO): <expensive field>
                             allowed-VIF-devices (SRO): <expensive field>
                                  possible-hosts ( RO): <expensive field>
                                     domain-type ( RW): pv
                             current-domain-type ( RO): pv
                                 HVM-boot-policy ( RW): 
                                 HVM-boot-params (MRW): 
                           HVM-shadow-multiplier ( RW): 1.000
                                       PV-kernel ( RW): 
                                      PV-ramdisk ( RW): 
                                         PV-args ( RW): 
                                  PV-legacy-args ( RW): 
                                   PV-bootloader ( RW): 
                              PV-bootloader-args ( RW): 
                             last-boot-CPU-flags ( RO): 
                                last-boot-record ( RO): <expensive field>
                                     resident-on ( RO): 9cbf654a-d889-4317-a37a-aa2f96ea3b69
                                        affinity ( RW): 9cbf654a-d889-4317-a37a-aa2f96ea3b69
                                    other-config (MRW): storage_driver_domain: OpaqueRef:47cb73c1-4143-f216-5c97-fc3977f291d9; is_system_domain: true; perfmon: <config><variable><name value="fs_usage"/><alarm_trigger_level value="0.9"/><alarm_trigger_period value="60"/><alarm_auto_inhibit_period value="3600"/></variable><variable><name value="mem_usage"/><alarm_trigger_level value="0.95"/><alarm_trigger_period value="60"/><alarm_auto_inhibit_period value="3600"/></variable><variable><name value="log_fs_usage"/><alarm_trigger_level value="0.9"/><alarm_trigger_period value="60"/><alarm_auto_inhibit_period value="3600"/></variable></config>
                                          dom-id ( RO): 0
                                 recommendations ( RO): 
                                   xenstore-data (MRW): 
                      ha-always-run ( RW) [DEPRECATED]: false
                             ha-restart-priority ( RW): 
                                           blobs ( RO): 
                                      start-time ( RO): 19700101T00:00:00Z
                                    install-time ( RO): 19700101T00:00:00Z
                                    VCPUs-number ( RO): 16
                               VCPUs-utilisation (MRO): <expensive field>
                                      os-version (MRO): <not in database>
                                    netbios-name (MRO): <not in database>
                              PV-drivers-version (MRO): <not in database>
              PV-drivers-up-to-date ( RO) [DEPRECATED]: <not in database>
                                          memory (MRO): <not in database>
                                           disks (MRO): <not in database>
                                            VBDs (SRO): 
                                        networks (MRO): <not in database>
                             PV-drivers-detected ( RO): <not in database>
                                           other (MRO): <not in database>
                                            live ( RO): <not in database>
                      guest-metrics-last-updated ( RO): <not in database>
                             can-use-hotplug-vbd ( RO): <not in database>
                             can-use-hotplug-vif ( RO): <not in database>
                        cooperative ( RO) [DEPRECATED]: <expensive field>
                                            tags (SRW): 
                                       appliance ( RW): <not in database>
                                          groups ( RW): 
                               snapshot-schedule ( RW): <not in database>
                                is-vmss-snapshot ( RO): false
                                     start-delay ( RW): 0
                                  shutdown-delay ( RW): 0
                                           order ( RW): 0
                                         version ( RO): 0
                                   generation-id ( RO): 
                       hardware-platform-version ( RO): 0
                               has-vendor-device ( RW): false
                                 requires-reboot ( RO): false
                                 reference-label ( RO): 
                                    bios-strings (MRO): 
                               pending-guidances ( RO): 
                                           vtpms ( RO): 
                   pending-guidances-recommended ( RO): 
                          pending-guidances-full ( RO): 
          
          tjkreidlT 1 Reply Last reply Reply Quote 0
          • tjkreidlT Offline
            tjkreidl Ambassador @Chrome
            last edited by tjkreidl

            @Chrome Do then just a "xe vm-list" and see if you recogniize any VMs other than the dom0 instance of XCP-ng.
            If there is nothing else showing up, you will need to try to find your other LVM storage.

            C 1 Reply Last reply Reply Quote 1
            • C Offline
              Chrome @tjkreidl
              last edited by

              @tjkreidl

              This is what showed up:

              uuid ( RO)           : 6dccd15c-2682-460c-9049-bdd210288c74
                   name-label ( RW): Control domain on host: vm
                  power-state ( RO): running
              

              I think I may have had some VMs on the SSD drive...but I guess the drive was wiped during the re-install?

              Also, when I login to Xen Orchestra, the SR I just re-attached shows as "disconnected".... so, I'm guess that's why I don't see any VMs.

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

                VM metadata isn't stored in the SR but in XAPI DB. If you removed it, then you lost all the VM metadata (VM name, description, number of disks, CPU, RAM etc.)

                However, if you don't formatted the SR itself, you should be able to find the actual data, then "just" recreate the VM and attach each disk to your recreated VM.

                Now the question is: do you have formatted your SR? If yes, you also lost data, not just metadata. If not, you need to re-introduce the SR and then recreate the associated PBD (the PBD is the "link" between your host and the SR, telling how to access data, eg the path of the local drive in your case)

                C 3 Replies Last reply Reply Quote 1
                • tjkreidlT Offline
                  tjkreidl Ambassador @Chrome
                  last edited by

                  @Chrome As M. Lambert says, you may be able to sue pbd-plug to re-attach the SR if you can sr-introduce the old SR back into the system.
                  If not, and if your LVM configuration has not been wiped out, here are some steps t try to recover it (it's an ugly process!):

                  1. Identify the LVM configuration:
                    Check for Backups: Look for LVM metadata backups in /etc/lvm/archive/ or /etc/lvm/backup/.
                    Use vgscan: This command will search for volume groups and their metadata.
                    Use pvscan: This command will scan for physical volumes.
                    Use lvs: This command will list logical volumes and their status.
                    Use vgs: This command will list volume groups.
                  2. Restore from Backup (if available):
                    Find the Backup: Locate the LVM metadata backup file (e.g., /etc/lvm/backup/<vg_name>).
                    Boot into Rescue Mode: If you're unable to access the system, boot into a rescue environment.
                    Restore Metadata: Use vgcfgrestore to restore the LVM configuration.
                  3. Recreate LVM Configuration (if no backup):
                    Identify PVs: Use pvscan to list available physical volumes.
                    Identify VGs: Use vgscan to identify volume groups if they are present.
                    Recreate PVs: If necessary, use pvcreate to create physical volumes.
                    Create VGs: If necessary, use vgcreate to create a new volume group.
                    Create LVs: If necessary, use lvcreate to create logical volumes.
                  4. Mount and Verify:
                    Mount the Logical Volumes: Mount the restored LVM volumes to their respective mount points.
                    Verify Data: Check the integrity of the data on the restored LVM volumes.
                  5. Extend LVM (if adding capacity):
                    Add a new disk: Ensure the new disk is recognized by the system.
                    Create PV: Use pvcreate on the new disk.
                    Add PV to VG: Use vgextend to add the PV to the volume group.
                    Extend LV: Use lvextend to extend the size of an existing logical volume.
                    Extend Filesystem: Use e2resize (for ext4) or resize2fs (for ext3) to extend the filesystem on the LV.
                  1 Reply Last reply Reply Quote 1
                  • C Offline
                    Chrome @olivierlambert
                    last edited by

                    @olivierlambert said in How to Re-attach an SR:

                    VM metadata isn't stored in the SR but in XAPI DB. If you removed it, then you lost all the VM metadata (VM name, description, number of disks, CPU, RAM etc.)

                    However, if you don't formatted the SR itself, you should be able to find the actual data, then "just" recreate the VM and attach each disk to your recreated VM.

                    Now the question is: do you have formatted your SR? If yes, you also lost data, not just metadata. If not, you need to re-introduce the SR and then recreate the associated PBD (the PBD is the "link" between your host and the SR, telling how to access data, eg the path of the local drive in your case)

                    Thanks for your reply! I wanted to get back to you yesterday, but had family obligations.

                    I did not format the SR, in fact, I was hoping after the re-install of XCP-ng (I re-installed to get IPv6 enabled), xcp-ng would just "pickup" the SR. I obviously didn't understand that there's much more to it than that.

                    1 Reply Last reply Reply Quote 0
                    • C Offline
                      Chrome @olivierlambert
                      last edited by

                      This post is deleted!
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                      • C Offline
                        Chrome @olivierlambert
                        last edited by Chrome

                        @tjkreidl

                        Thank you for the detailed reply, I will need much hand holding through this process! I waned to respond yesterday to your helpful instructions, but I was with the family. So, I am going to try these commands now:

                        /etc/lvm/backup:
                        -rw------- 1 root root 1330 May 30 19:53 XSLocalEXT-de0e7bd7-e938-78a8-1c1f-2eac2639298d
                        
                        /etc/lvm/archive/:
                        Nothing in this directory
                        
                        vgscan:
                          Reading all physical volumes.  This may take a while...
                          Found volume group "XSLocalEXT-de0e7bd7-e938-78a8-1c1f-2eac2639298d" using metadata type lvm2
                        
                        pvscan:
                          PV /dev/nvme0n1   VG XSLocalEXT-de0e7bd7-e938-78a8-1c1f-2eac2639298d   lvm2 [931.50 GiB / 0    free]
                          Total: 1 [931.50 GiB] / in use: 1 [931.50 GiB] / in no VG: 0 [0   ]
                        
                        lvs:
                         LV                                   VG                                              Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
                          de0e7bd7-e938-78a8-1c1f-2eac2639298d XSLocalEXT-de0e7bd7-e938-78a8-1c1f-2eac2639298d -wi------- 931.50g              
                        
                        vgs:
                          VG                                              #PV #LV #SN Attr   VSize   VFree
                          XSLocalEXT-de0e7bd7-e938-78a8-1c1f-2eac2639298d   1   1   0 wz--n- 931.50g    0 
                        

                        So, I got this far... and then I booted off the INSTALLER USB drive, to see if I get to rescue mode... but I noticed that there's a "restore" option, so, I decided to try that.

                        To my delight, it restored the connection to the nvme SR, which looks like it had 4 VMs on it... and they appear to be up and running now. Sweet!

                        The other VMs I had... looks like I stored them on the SSD... which I reinstalled xcp-ng on...so, I guess those are gone? So, lesson learned there.

                        tjkreidlT 1 Reply Last reply Reply Quote 0
                        • tjkreidlT Offline
                          tjkreidl Ambassador @Chrome
                          last edited by tjkreidl

                          @Chrome Fantastic! Please mark my post as helpful if you found it as such. Was traveling much of today, hence the late response.

                          BTW, it's always good to make a backup and/or archive of your LVM configuration anytime you change it, as the restore option is the cleanest way to deal with connectivity issues if there is some sort of corruption. It's saved my rear end before, I can assure you!

                          Yeah, if the SSD drive got wiped, there's no option to get those back unless you made a backup somewhere of all that before you installed XCP-ng onto it.

                          BTW, another very useful command for LVM is "vgchange -ay" which will attempt to renew VG information if a VG seems missing or the like.

                          C 1 Reply Last reply Reply Quote 1
                          • C Offline
                            Chrome @tjkreidl
                            last edited by

                            @tjkreidl Yes, thank you so much for all your help! I will be diving in backups.... even something on a schedule. I appreciate your patience, and your teachings! 🙂 All the best to you. 🙂 It was a pleasure. I hope I correctly marked your post as helpful, it really was.

                            tjkreidlT 1 Reply Last reply Reply Quote 1
                            • tjkreidlT Offline
                              tjkreidl Ambassador @Chrome
                              last edited by

                              @Chrome Cheers -- always glad to help out. I put in many thousands of posts on the old Citrix XenServer site, and am happy to share whatever knowledge I still have, as long as it's still relevant! In a few years, it probably won't be, so carpe diem!

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                              • olivierlambertO olivierlambert marked this topic as a question
                              • olivierlambertO olivierlambert has marked this topic as solved
                              • olivierlambertO Offline
                                olivierlambert Vates 🪐 Co-Founder CEO
                                last edited by

                                Hehe another great example of why a community is fantastic!! (it's a bit sad that Citrix never realized it)

                                tjkreidlT 1 Reply Last reply Reply Quote 1
                                • tjkreidlT Offline
                                  tjkreidl Ambassador @olivierlambert
                                  last edited by

                                  @olivierlambert Agreed. The Citrix forum used to be very active, but especially since Citrix was taken over, https://community.citrix.com has had way less activity, sadly.
                                  It's still gratifying that a lot of the functionality still is common to both platforms, although as XCP-ng evolves, there will be continually less commonality.

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