Andy,
I was in the same boat you are in trying to figure out
which was better. I originally started out with NFS being served up
through a NetApp SAN and was running 100+ virtual machines through it across 4
servers. The problem was performance was terrible. It works ok if you are
serving up a machine here or there and all they do is run. However, if you are
going to script out your builds and have a 4 or more machines being built at
once that is when you will see the performance hit. Once the creation is
completed performance will usually go back to normal.
I did recently switch to iscsi in an ocfs2 format
clustered on 2 servers for testing and it is a lot better. However, there is a
current bug with it tht Novell is writing a patch for me on and I should
hopefully have it today or tomorrow. I also have 2 other servers that have
their own iscsi volumes tied to them. All in all I am extremely happy with the
consistent performance I am getting for the ISCSI volumes and highly recommend
them.
Pros and cons:
NFS:
Extemely easy to manage. And if you SAN provider has
de-dupe support the NFS volumes de-dupe really good. But Performance is bad and
will cause some thinning in the hairline.
Iscsi:
Consistent reliable performance can be used as a cluster
aware file system depending how you format it out.
Doesn’t de-dupe nearly as well as NFS does and isn’t
as easy to manage or resize on the fly like NFS so you need to keep an eye on
your volumes and manage them a little more closely.
Hope this helps if you have further questions shoot me an
email joe.coleman@xxxxxxxxxxxxxxxxxx
Message: 5
Date: Mon, 1 Feb 2010 22:57:19 -0600
From: Andy Pace <APace@xxxxxxxxxxxxx>
Subject: [Xen-users] iSCSI vs NFS
To: "xen-users@xxxxxxxxxxxxxxxxxxx"
<xen-users@xxxxxxxxxxxxxxxxxxx>
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<B915EE0870BDF348816B665DBE85F1652A65125FC1@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
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Which is the easiest to manage with multiple (lets say
hundreds) of xen VM's without sacrificing performance, and why?
What are the pro's and cons to each? From my research,
iSCSI seems the way to go here, but all the SAN/NAS vendor's I've spoken with
live and die *NFS*, which I've had some serious issues with in the past in so
far as scalability and performance...
Just thought i'd get an outside/un-biased (i hope!)
opinion...
