All this complexity makes me question the advantages of having all hosts in the same pool.

My setup is pretty basic.
I have two hosts in the pool, one for running VMs on local storage and one for DR backups on local storage.
I'd like to setup shared storage so i could run the VMs on multiple hosts and seamlessly move them between hosts without migrating storage too.

To setup shared storage would this be on an xcp-ng host or totally independent of xcp-ng?

Can I restart the slave and install patches if the master has not been patched yet?

Have restarted the tool stack but no different.

When I view hst110 I see:

I was tempted to restart it however it has Patches pending installation after a restart and as the mater is not fully patched I thought best not to restart it. I understand the master needs to be patched first.

I just checked xsconsole on hst110 and it shill shows pool master unavailable

Do I need to change the pool master used by the slave?

I have only had to do this once before but remember it going fairly smoothly at the time. (As smooth as you can expect a host failure to be anyways)

Apologies, I missed that. I have run the command and now see:

hst103 is the new pool master. hst100 is the old pool master that failed.

In XO I can only see hst103 under hosts however all three hosts are listed under the pool:

Yes you'd run that command on the pool master.

I linked this earlier in the thread, it outlines the process you need to follow:
https://docs.xenserver.com/en-us/xenserver/8/dr/machine-failures.html

Let us know if this works!

No I didn't. Does this need to be run on the slave itself or the new master?

When you say "after selecting a new master" do you mean after I did this on the new master?

xe pool-emergency-transition-to-master

Edit:
Found this which shows this is run on the new pool master:
https://www.ervik.as/how-to-change-the-pool-master-in-a-xenserver-farm/

xe pool-recover-slave

after selecting a new master?

I expect this is because the pool slave is still looking for the old pool master and has not identified that a new pool master exists.

What needs to be done to the pool slave to have it appear as a member of the pool again?

The host with my DR VM does not show as being part of the pool

Does I need to add it to the new pool master?

OK, pool is now up and accessible

Now I am restoring a VM that resided on the failed master. Fingers crossed.

Interestingly, the master failed to boot after installing patched. I had also installed the patches on the slave but not yet rebooted the slave. When I elevated the slave to master it said it would reboot in 10 seconds and I thought SHIT what if this fails too.

I guess the learning here is to only install the patches when the host is ready to be restarted, not before.

Thanks for the quick response.

I have updates for all hosts but I understand I need to patch the host master first so that is what I was doing.

Will I lose all my pool settings like VLANs etc?

Thank you.

So there is no temporary workaround to get the VMs up again whilst I try to fix the pool master?

I guess I could:

• Make the slave the new master
• Rebuild the failed master
• Elevate the rebuilt master to be the new pool master

xe pool-emergency-transition-to-master
followed by
xe-toolstack-restart

This will make that slave the new pool master. You should only do this though if the current pool master for sure dead.

This may also be useful:
https://docs.xenserver.com/en-us/xenserver/8/dr/machine-failures.html

I know this host is a pool member but this message says otherwise:

Not sure what to do here...