[Linux-cluster] Starter Cluster / GFS
rossnick-lists at cybercat.ca
Wed Nov 10 12:07:33 UTC 2010
> If you want the FS mounted on all nodes at the same time then all those
> nodes must be a part of the cluster, and they have to be quorate (majority
> of nodes have to be up). You don't need a quorum block device, but it can
> be useful when you have only 2 nodes.
At term, I will have 7 to 10 nodes, but 2 at first for initial setup and
testing. Ok, so if I have a 3 nodes cluster for exemple, I need at least 2
nodes for the cluster, and thus the gfs, to be up ? I cannot have a running
gfs with only one node ?
> If you are only ever going to have the SAN volume mounted on one device at
> a time, don't bother with GFS and make the SAN block device a fail-over
> resource so that only one node can mount it at a time, and put a normal
> non-shared FS on it. You will get better performance.
I do need a shared file-system, I am aware of the added latency, we
currently have some latency on our xSan setup. But we do also need on some
services an additional block-device that is accessed only by one node and is
indeed failed-over another node when a node fail.
> The number of journals needs to be equal to or greater than the number of
> nodes you have in a cluster. e.g. if you have 5 nodes in a cluster, you
> need at least 5 journals. If you think you might upgrade your cluster to
> 10 nodes at some point in the future, then create 10 journals, as this
> needs to be done at FS creation time.
That I got. It's the size that I don't know how to figure out. Will 32 megs
will be enough ? 64 ? 128 ?
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