I'm still trying to figure out why someone would use MSCS on ESX:
MSCS is primarily used for HARDWARE-LEVEL fault tolerance (it won't help if the application crashes, so much as if the hardware dies).
VMotion can be used in place of MSCS for hardware-level fault tolerance, IIRC, which negates the need for MSCS within a VM.
-----Original Message----- From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of M. Vaughn Stewart Sent: Saturday, October 27, 2007 5:08 PM To: Jack Lyons Cc: Page, Jeremy; toasters@mathworks.com Subject: Re: A-SIS questions
FlexClone will clone a datastore, for VM level cloning granularity you gonna have to wait I think something is just around the corner.
As for MSCS you need RDMs as VMDKs are not supported with MSCS
RDMs can be either FCP or iSCSI VMDKs can be on NFS or VMFS (which is over FCP or iSCSI)
We are in the process of testing ESX on NFS. We have 2 out of 60 on NFS now. I just started thinking about using flexclones, is any one using flex clones with NFS for creating clones of VM's.
Also, from what I have read, to use MSCS I need to use an RDM from iscsi or FC luns...correct?
Thanks Jack
M. Vaughn Stewart wrote:
Jeremy,
A-SIS has a slight write performance penalty (a few points) and typically also sees a slight read performance gain (of the same amount), so in short customers who are using it love it. Now you don't use it everywhere, like on DB files.
As for VMware on NFS, enjoy your solution it rocks, don't take my word for it. Google VMware on NFS and sort by date, you'll have allot of reading to do. Quotes from executives at EMC and VMware just support what you are deploying. Make sure to see NetApp's TR3428 for deployment details.
See ya Vaughn
I have read some of the info on how A-SIS works but I have a couple of questions:
- Assuming an average compression rate (say /home with random docs
in it) how much of a performance hit does it impose 2) Does it change how much data is sent over the wire when you use SnapMirror/SnapVault? I.e. if I get 30% compression on a 1 gig snapshot do I send 1 gig or 700 mb to update my target?
Oh, and for the folks who helped earlier, we are moving our Oracle and ESX systems to NetApp, the pSeries will be fibre connected, at least at first but the ESX stuff is all going on NFS.
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