Hi.
I vaguely recall seeing somewhere the limitation list for clustering vsphere hosts, which basically came down to vmotion limitations.
By that I mean that it was a document describing how two hosts have to match and differences they can afford to have.
I'd greatly appreciate it if someone point me towards that info.
Also, am I right to assume that a cluster configuration is quite workable without a shared datastore?
How much of a performance hit is involved in refraining from it (MS SQL usage scenario)?
Wouldn't shared storage mean a single point of failure, kind of defeating the idea of clustering?
Thank you so much for your answers.
Alex.
Hi friend,
First I should ask, what's clustering points? Fail-over and load-balancing.
Not in VMware vCenter, on any clustering system, resources are shared between nodes. You need to share virtual machine's configuration and VMDKs.
Absolutely, you need to shared storage to configure clusters and use clustering abilities.
About SQL performance on vMotion, based on your hardware specification and especially your network bandwidth, vMotion can do migrate VM to another host faster.
You can use flash memory as local storage for store ESXi files and configuration and mix your SAS hard disks to shared storage by VSA, OpenFiler, FreeNAS and etc.
No need to buy expensive hardware for small scale environments.
BR
So, to reiterate, if I have two identical servers, both with their own respective local datastores, they CANNOT behave as a cluster?
Hi friend,
Exactly, you can join them to cluster but HA, DRS and other abilities won't work.
If you want to use shared storage, I recommend you to use a desktop or server as storage server, it's very cheaper than storage devices.
BR
If you are running vSphere 5 yes they can usinge the VMware Storage Appliance (VSA) this will allow each host to present storage that will act as shared storage enabling you to cofigure a vSPhere cluster utlizing HA and/or DRS or as Davoud recommended setting up a third machine to act as storage server presenting NFS or as an iSCSI server -
