On Dec 4, 2009, at 11:54 AM, Jeffry Molanus wrote:
In my experience, cloning is done for basic provisioning, so how
would
you get
to the case where you could not clone any particular VM?
-- richard
Well, a situation where this might come in handy is when you have
your typical ISP provider that has multiple ESX hosts with multiple
datastores. ESX has limits on how many datastores it can have so
cloning filesystems over and over will only get you that far. (16 I
believe?). Or a VDI environment for schools for instance? Instead of
cloning a complete zfs fs; you can clone the freshmen-gold.vmkd
times the new subscribed students?
For ESX, the current limit of NFS datastores is 64.
Let's assume the scenario of the school? You have a NFS export
containing gold images with different pre installed applications or
whatever. How would you rapidly deploy 500 new gold-images? Copy
them 500 times? If you clone them on the ESX side; you would also
have to copy them. Moreover why copy->dedup if you can prevent the
dedup process all together? Since the dedup process in inline; it
could affect the storage performance as it goes along.
In my experience, this is why people are using iSCSI instead of NFS
for ESX.
ESX has a LUN limit of 256, so eventually you'll need another box :-)
This is a bit of a shame, but the real solution resides in VMWare's
court.
Apparently the claim is that NFS mounts consume memory and therefore
the restriction. Again, this is a bit of a shame because of the
relative
cost of RAM versus thousands of man-hours spent gnashing teeth on the
issue.
-- richard
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