<![CDATA[How to Re-attach an SR]]>Hey all!

I'll try to keep this short. I re-installed xcp-ng 8.3 because I wanted to run a dual stack ipv4 and ivp6.

I have three drives in my system.

SSD - /dev/sda (xcp-ng)
NVMe1 - /dev/nvme0n1 (SR)
NVMe2 - /dev/nvme1n1 (SR)

I know I should have checked where exactly the VMs are stored and I should have made a backup, but I didn't. So, that's on me.

 lsblk
NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
nvme0n1     259:5    0 931.5G  0 disk 
nvme1n1     259:0    0   477G  0 disk 
├─nvme1n1p4 259:4    0   706M  0 part 
├─nvme1n1p2 259:2    0    16M  0 part 
├─nvme1n1p3 259:3    0 463.1G  0 part 
└─nvme1n1p1 259:1    0   100M  0 part 
sda           8:0    0 465.8G  0 disk 
├─sda2        8:2    0    18G  0 part 
├─sda5        8:5    0     4G  0 part /var/log
├─sda3        8:3    0   512M  0 part /boot/efi
├─sda1        8:1    0    18G  0 part /
└─sda6        8:6    0     1G  0 part [SWAP]

After I re-installed xcp-ng, I don't have any SR's available. I am pretty sure that I had both nvme drive setup as SR... how can I re-attach them?

I haven't be able to find anything solid online.

I MAY have had VM installed on the SSD drive... are those gone because I reinstlaled xcp-ng on that drive?

]]>https://xcp-ng.org/forum/topic/10903/how-to-re-attach-an-srRSS for NodeFri, 13 Mar 2026 07:22:07 GMTSat, 31 May 2025 15:15:18 GMT60<![CDATA[Reply to How to Re-attach an SR on Tue, 03 Jun 2025 11:54:06 GMT]]>@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.

]]>https://xcp-ng.org/forum/post/93627https://xcp-ng.org/forum/post/93627Tue, 03 Jun 2025 11:54:06 GMT<![CDATA[Reply to How to Re-attach an SR on Tue, 03 Jun 2025 08:09:33 GMT]]>Hehe another great example of why a community is fantastic!! (it's a bit sad that Citrix never realized it)

]]>https://xcp-ng.org/forum/post/93618https://xcp-ng.org/forum/post/93618Tue, 03 Jun 2025 08:09:33 GMT<![CDATA[Reply to How to Re-attach an SR on Tue, 03 Jun 2025 02:35:25 GMT]]>@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!

]]>https://xcp-ng.org/forum/post/93612https://xcp-ng.org/forum/post/93612Tue, 03 Jun 2025 02:35:25 GMT<![CDATA[Reply to How to Re-attach an SR on Tue, 03 Jun 2025 01:06:16 GMT]]>@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.

]]>https://xcp-ng.org/forum/post/93611https://xcp-ng.org/forum/post/93611Tue, 03 Jun 2025 01:06:16 GMT<![CDATA[Reply to How to Re-attach an SR on Tue, 03 Jun 2025 00:48:35 GMT]]>@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.

]]>https://xcp-ng.org/forum/post/93609https://xcp-ng.org/forum/post/93609Tue, 03 Jun 2025 00:48:35 GMT<![CDATA[Reply to How to Re-attach an SR on Mon, 02 Jun 2025 20:38:37 GMT]]>@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.

]]>https://xcp-ng.org/forum/post/93603https://xcp-ng.org/forum/post/93603Mon, 02 Jun 2025 20:38:37 GMT<![CDATA[Reply to How to Re-attach an SR on Mon, 02 Jun 2025 14:49:38 GMT]]>@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.

]]>https://xcp-ng.org/forum/post/93552https://xcp-ng.org/forum/post/93552Mon, 02 Jun 2025 14:49:38 GMT<![CDATA[Reply to How to Re-attach an SR on Sun, 01 Jun 2025 10:52:10 GMT]]>@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.
]]>https://xcp-ng.org/forum/post/93509https://xcp-ng.org/forum/post/93509Sun, 01 Jun 2025 10:52:10 GMT<![CDATA[Reply to How to Re-attach an SR on Sun, 01 Jun 2025 06:35:32 GMT]]>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)

]]>https://xcp-ng.org/forum/post/93504https://xcp-ng.org/forum/post/93504Sun, 01 Jun 2025 06:35:32 GMT<![CDATA[Reply to How to Re-attach an SR on Sun, 01 Jun 2025 01:21:20 GMT]]>@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.

]]>https://xcp-ng.org/forum/post/93502https://xcp-ng.org/forum/post/93502Sun, 01 Jun 2025 01:21:20 GMT<![CDATA[Reply to How to Re-attach an SR on Sun, 01 Jun 2025 00:22:27 GMT]]>@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.

]]>https://xcp-ng.org/forum/post/93500https://xcp-ng.org/forum/post/93500Sun, 01 Jun 2025 00:22:27 GMT<![CDATA[Reply to How to Re-attach an SR on Sun, 01 Jun 2025 00:17:02 GMT]]>@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):
]]>https://xcp-ng.org/forum/post/93499https://xcp-ng.org/forum/post/93499Sun, 01 Jun 2025 00:17:02 GMT<![CDATA[Reply to How to Re-attach an SR on Sun, 01 Jun 2025 00:15:35 GMT]]>@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?

]]>https://xcp-ng.org/forum/post/93498https://xcp-ng.org/forum/post/93498Sun, 01 Jun 2025 00:15:35 GMT<![CDATA[Reply to How to Re-attach an SR on Sun, 01 Jun 2025 00:05:40 GMT]]>@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?

]]>https://xcp-ng.org/forum/post/93497https://xcp-ng.org/forum/post/93497Sun, 01 Jun 2025 00:05:40 GMT<![CDATA[Reply to How to Re-attach an SR on Sat, 31 May 2025 23:57:35 GMT]]>@tjkreidl How do I get the UUID for the nvme1n1 drive? Its not listed on xe sr-list .....

]]>https://xcp-ng.org/forum/post/93496https://xcp-ng.org/forum/post/93496Sat, 31 May 2025 23:57:35 GMT<![CDATA[Reply to How to Re-attach an SR on Sat, 31 May 2025 23:21:54 GMT]]>@Chrome OK, now try "xe sr-introduce" (check the syntax for the full command syntax you need), depending on what your connection type is:

xe sr-introduce uuid=<device uuid> shared=true type=lvmohba name-label=<name>

xe sr-introduce uuid=<device uuid> shared=true type=lvmoiscsi name-label=<name>

xe sr-introduce uuid=<device uuid> shared=true type=nfs name-label=<name>

If you are lucky and the interface still exists by which the SR was attached, that might do the trick.

]]>https://xcp-ng.org/forum/post/93494https://xcp-ng.org/forum/post/93494Sat, 31 May 2025 23:21:54 GMT<![CDATA[Reply to How to Re-attach an SR on Sat, 31 May 2025 18:56:48 GMT]]>@tjkreidl said in How to Re-attach an SR:

xe sr-list

Don't completely remember... I would have kept things as default or basic as possible. Likely LVM is probably how I created them.

xe sr-list
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)                : 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
]]>https://xcp-ng.org/forum/post/93491https://xcp-ng.org/forum/post/93491Sat, 31 May 2025 18:56:48 GMT<![CDATA[Reply to How to Re-attach an SR on Sat, 31 May 2025 18:15:06 GMT]]>No metadata backup? All that info should be contained within. Otherwise, it could be a long, painful process. Are there LVM drives or how were they initially created?
I assume "xe sr-list" shows nothing or?

]]>https://xcp-ng.org/forum/post/93488https://xcp-ng.org/forum/post/93488Sat, 31 May 2025 18:15:06 GMT