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Re: [Xen-users] Shared Storage

On 25/04/2011 18:34, John Madden wrote:
I would honestly prefer to manage hundred of LVs instead of hundreds of
LUNs. I'm just concerned about the iSCSI bottleneck (if any) if I were
to create an LVM VG using a single iSCSI LUN for about 50 - 100 LVs. Any
advice is appreciated.

I'd be more concerned over iSCSI itself being able to scale based on your workload, especially if you're doing it over GbE. Even 50 VMs doing relatively little though concurrently could cause problems given the nature of iSCSI (TCP overhead, latency of ethernet, etc).
When you say this, are you refering to the suitation where I would have 1 LUN per VM (i.e. 50 LUNs)? I would be doing this over GbE, however I would be using trunking
My feel for this is that the fewer-LUN-more-LV route would be more efficient because you'll have fewer block device queues and multipath call-outs and such but that's just a guess on my part.
Interesting. I have had a comment on this list suggesting the opposite.
Test it out, see which one is better. If there's no difference, go with the one that's easier to manage.
Hands down mamanging LVM is my number one choice. Ideally I would just like to set up the iSCSI connections once and just leave it

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