@cairoti said in "Virtual Disk Not On Preferred Path" error on Dell Storages when mapping volumes:

The description below appears in the mapped volume in XO:

I don't know if the image has any relation to the problem.

The "Multipathing" option was not enabled on the hosts in the pool. So even though there was more than one connection to the Dell Storage, the warning message was displayed. The controller to be used could be 0 or 1. But because "Multipathing" was disabled, the storage automatically switched from 1 to 0 for some mapped volumes because it believed there was only one possible path.

I consider this issue resolved!

@Andrew, @bvitnik and @DustinB In my tests, I did the following. I did this process twice and it worked. To simulate a hardware failure on the master node, I simply turned it off.

If the master pool is down or unresponsive due to a hardware failure, follow these steps to restore operations:

1. Use an SSH client to log in to a slave host in the pool.

2. Run the following command on the slave host to promote it as the new pool master:

xe pool-emergency-transition-to-master

3. Confirm the change of the pool master and verify the hosts present in it:

xe pool-list

xe host-list

Even if it is down, the old master node will appear in the listing.

4. Remap the pool in XCP-ng or XO using the IP of the new master node.

5. After resolving the hardware issues on the old master node, start it up. When it finishes booting, it will be recognized as a slave node.

In testing, I did not need to run any other commands. However, if the node is not recognized, try typing on it after accessing it via SSH: xe pool-recover-slaves

I didn't understand why it worked. It seemed like "magic"!

@florent I couldn't map it directly to the XO, so I mounted it on Linux.

@florent It's actually only 3TB. It's a local S3 mount on the XO server that I mapped. The size shown is wrong.

@florent After setting a 32 character hexadecimal password, encryption was applied.

My question now is whether encryption is applied only “to the remote drive that acts as a vault” or to each stored file.

What should I configure as a key? Typing the characters didn't work.

Version: Xen Orchestra, commit 6277a

@Andrew, @bvitnik and @DustinB In my tests, I did the following. I did this process twice and it worked. To simulate a hardware failure on the master node, I simply turned it off.

If the master pool is down or unresponsive due to a hardware failure, follow these steps to restore operations:

1. Use an SSH client to log in to a slave host in the pool.

2. Run the following command on the slave host to promote it as the new pool master:

xe pool-emergency-transition-to-master

3. Confirm the change of the pool master and verify the hosts present in it:

xe pool-list

xe host-list

Even if it is down, the old master node will appear in the listing.

4. Remap the pool in XCP-ng or XO using the IP of the new master node.

5. After resolving the hardware issues on the old master node, start it up. When it finishes booting, it will be recognized as a slave node.

In testing, I did not need to run any other commands. However, if the node is not recognized, try typing on it after accessing it via SSH: xe pool-recover-slaves

I didn't understand why it worked. It seemed like "magic"!

@DustinB I use the open community version.

@DustinB I use a dedicated Dell SAN storage.

I am doing a lot of testing before putting my environment into production.

Suppose the pool has two nodes, one master node and the other a slave node. In case the master node fails due to hardware issues, I saw that the slave node can be changed to master using the command "xe pool-emergency-transition-to-master".

But when the old master server is repaired, how can I add it back? Won't I have two masters at the same time? Will a conflict occur?

In the tests I performed, when shutting down the master node, the VMs running on it were also shut down and not migrated to the slave node.

Links consulted:

https://xcp-ng.org/forum/topic/8361/xo-new-pool-master
https://xcp-ng.org/forum/topic/4075/pool-master-down-what-steps-need-done-next

@cairoti said in "Virtual Disk Not On Preferred Path" error on Dell Storages when mapping volumes:

The description below appears in the mapped volume in XO:

I don't know if the image has any relation to the problem.

The "Multipathing" option was not enabled on the hosts in the pool. So even though there was more than one connection to the Dell Storage, the warning message was displayed. The controller to be used could be 0 or 1. But because "Multipathing" was disabled, the storage automatically switched from 1 to 0 for some mapped volumes because it believed there was only one possible path.

I consider this issue resolved!

The description below appears in the mapped volume in XO:

I don't know if the image has any relation to the problem.