TOPIC:

Hi,

Had a weird issue recently where I turned off my 2 servers and I could not get my iscsi storage back. It was late, I was in deep and had to nuke and install xen with direct attached disks and restore. This shook my confidence in ha-lizard, but after looking around everywhere, there is nothing that can do what it does. So, I am going to try again, but have some questions:

1. In a 2 node pool using noSAN, can I run vm's on both the pool master and the slave? Or should everything run on the pool master and only on the slave in a maintenance / failed server scenario?

2. I have two Netscaler VPX appliances that run in a HA pair (they do not require XenServer or ha-lizard for HA) so I want one to run on the pool master and one to run on the slave, with ha turned off, but using the ha-lizard iscsi storage - is this ok? (There are other windows vm's too that will be protected by ha-lizard ha)

3. Can I apply XenServer hotfixes (current version, not XenServer upgrades) without causing any damage to ha-lizard?

4. What is the correct procedure to shutdown BOTH XenServers in a ha-lizard protected pool? (I had to move the servers in a data centre hence shutdown of both systems)

5. When creating a ha-lizard pool how is the storage created? Eg I have 2 disks in RAID 1+0 for XenServer (sda) and 6 disks in RAID 1+0 per server for the ha-lizard storage (sdb). During XenServer install should I tell XenServer to only use sdb for virtual machine storage? Or should I not allow XenServer to create any storage and let ha-lizard do this when it's installed?

Sorry for all the questions, I am keen to rebuild this and learn what I did wrong and to make it more robust. I am keen to roll this out using XenServer 7 when official support is available

Regards,

Adam

See responses inline below. Also, we have should have new releases available in the next week or so with several improvements. First release will be for Xenserver 6.5 deployments and then a new version supporting XenServer 7.

1. In a 2 node pool using noSAN, can I run vm's on both the pool master and the slave? Or should everything run on the pool master and only on the slave in a maintenance / failed server scenario?

You can freely run VMs on both the master and slave simultaneously.

2. I have two Netscaler VPX appliances that run in a HA pair (they do not require XenServer or ha-lizard for HA) so I want one to run on the pool master and one to run on the slave, with ha turned off, but using the ha-lizard iscsi storage - is this ok? (There are other windows vm's too that will be protected by ha-lizard ha)

Yes. This is fine. You will get the benefit of the storage replication. The application level HA in your appliances will handle the rest.

3. Can I apply XenServer hotfixes (current version, not XenServer upgrades) without causing any damage to ha-lizard?

Yes, but care should be taken to ensure that the upgrade procedure is followed which ensures that the storage is always available. Also, it is preferred to apply all updates at once (which XenServer allows for) so that you don't have to constantly reboot the hosts and move VMs back and forth.

4. What is the correct procedure to shutdown BOTH XenServers in a ha-lizard protected pool? (I had to move the servers in a data centre hence shutdown of both systems)

- disable HA
- shutdown all VMs
- shutdown the hosts

5. When creating a ha-lizard pool how is the storage created? Eg I have 2 disks in RAID 1+0 for XenServer (sda) and 6 disks in RAID 1+0 per server for the ha-lizard storage (sdb). During XenServer install should I tell XenServer to only use sdb for virtual machine storage? Or should I not allow XenServer to create any storage and let ha-lizard do this when it's installed?

Either way would work. If you tell the XenServer installer to use sdb for local storage and then tell the ha-lizard installer to convert the local storage, it will simply remove the local SR which frees sdb. We then use sdb as the backing disk to DRBD.

If you don't choose any local storage during the XenServer installation, you simply declare sdb as the backing disk during the ha-lizard installation.

The end result is the same in either case.