Which hosts belong in what pool when running local storage?
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@bnrstnr said in Which hosts belong in what pool when running local storage?:
@DustinB3403 said in Which hosts belong in what pool when running local storage?:
Which allows your VMs to just move when needed and not ever have to be touched by hand.
I've never tried this, but do you need shared storage for this?
Should not. It's like "Storage vMotion" when the storage is not shared.
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I'll just want to confirm that I will go with one pool for production and one pool for development and benchmarking.
Citrix recommendation for Xenserver is to have production & development hosts in separate pools and it makes sense just from avoiding avoiding human mistakes as well.
Also all the hosts in the pool share the same network config so it also makes sense to have development in it's own pool in case one want to test something out.
Ideally, I'd have one set of switches for each pool as well, but I'll have to settle for different vlans for now - for budgetary reasons.
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@Pete-S said in Which hosts belong in what pool when running local storage?:
I'll just want to confirm that I will go with one pool for production and one pool for development and benchmarking.
Citrix recommendation for Xenserver is to have production & development hosts in separate pools and it makes sense just from avoiding avoiding human mistakes as well.
Also all the hosts in the pool share the same network config so it also makes sense to have development in it's own pool in case one want to test something out.
Ideally, I'd have one set of switches for each pool as well, but I'll have to settle for different vlans for now - for budgetary reasons.
Sounds like a reasonable plan.
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Just wanted to provide an update.
I started as intended and put all hosts in two pools but I have changed it since. It simply doesn't work well if you aren't running shared storage and doing HA in the pool.
So now all hosts are individual hosts and don't belong to any pool. I found it to be the most flexible setup when you're not using shared storage.
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@Pete-S said in Which hosts belong in what pool when running local storage?:
Just wanted to provide an update.
I started as intended and put all hosts in two pools but I have changed it since. It simply doesn't work well if you aren't running shared storage and doing HA in the pool.
So now all hosts are individual hosts and don't belong to any pool. I found it to be the most flexible setup when you're not using shared storage.
Are you still able to live migrate a machine from one server to another?
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@dafyre said in Which hosts belong in what pool when running local storage?:
@Pete-S said in Which hosts belong in what pool when running local storage?:
Just wanted to provide an update.
I started as intended and put all hosts in two pools but I have changed it since. It simply doesn't work well if you aren't running shared storage and doing HA in the pool.
So now all hosts are individual hosts and don't belong to any pool. I found it to be the most flexible setup when you're not using shared storage.
Are you still able to live migrate a machine from one server to another?
Yes, it works fine. It's shared nothing live migration. Take a while to do it since both local storage and memory is migrated.
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@Pete-S said in Which hosts belong in what pool when running local storage?:
@dafyre said in Which hosts belong in what pool when running local storage?:
@Pete-S said in Which hosts belong in what pool when running local storage?:
Just wanted to provide an update.
I started as intended and put all hosts in two pools but I have changed it since. It simply doesn't work well if you aren't running shared storage and doing HA in the pool.
So now all hosts are individual hosts and don't belong to any pool. I found it to be the most flexible setup when you're not using shared storage.
Are you still able to live migrate a machine from one server to another?
Yes, it works fine. It's shared nothing live migration. Take a while to do it since both local storage and memory is migrated.
Right. But it is good to know that you are able to do that if needed... such as planned maintenance on one of the hosts.
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@dafyre said in Which hosts belong in what pool when running local storage?:
@Pete-S said in Which hosts belong in what pool when running local storage?:
@dafyre said in Which hosts belong in what pool when running local storage?:
@Pete-S said in Which hosts belong in what pool when running local storage?:
Just wanted to provide an update.
I started as intended and put all hosts in two pools but I have changed it since. It simply doesn't work well if you aren't running shared storage and doing HA in the pool.
So now all hosts are individual hosts and don't belong to any pool. I found it to be the most flexible setup when you're not using shared storage.
Are you still able to live migrate a machine from one server to another?
Yes, it works fine. It's shared nothing live migration. Take a while to do it since both local storage and memory is migrated.
Right. But it is good to know that you are able to do that if needed... such as planned maintenance on one of the hosts.
True! And with 10GbE and SSD storage it's not too bad.
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Pooling the resources doesn't mean you need HC or even HA.
Pooling just says, if this host goes down some other hosts is ready to take the workload. You shouldn't be experiencing any issues like what you've described from using pooling.
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@DustinB3403 said in Which hosts belong in what pool when running local storage?:
Pooling the resources doesn't mean you need HC or even HA.
Pooling just says, if this host goes down some other hosts is ready to take the workload. You shouldn't be experiencing any issues like what you've described from using pooling.
You are right and you are wrong.
A pool is just a pool of hosts as you said but you actually need HA for another host to take the workload automatically. You could do it manually but in either case, the VMs storage or a copy of it needs to be accessible for the new host. So you need some kind of "shared storage" solution (SAN/distributed FS/replicated backups/whatever) to "move" a VM from a failed host.
With xenserver the pool is administrated through the pool master. If the pool master dies another host takes the master role - if you have HA enabled. If you don't have HA the entire pool will become unreachable. It's not fun.
https://docs.citrix.com/en-us/xenserver/current-release/hosts-pools.htmlThere are other issues as well, like when moving a standalone host to a pool all VMs on local storage will be erased.
All in all, unless you have some kind of shared storage solution/replication going on, it's less restrictive to have standalone hosts. At least with xenserver. You can still manage them centrally and move VMs between them as you please.
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So to answer my own question:
"Which hosts belong in what pool when running local storage?"The answer is none - at least with xenserver. Don't use pools when using local storage.
