Hi Milazzo,
You are absolutely correct, and beyond lower performance there's an issue of maintaining the CIFS connection in the case of cluster failover.
However, if there's one thing that's true about I.T. it's that if something is _possible_, someone somewhere will have a set of circumstances (not necessarily technical, often financial or political), where that solution makes sense for them.
10 years ago it was a very hard sell to get people to access enterprise databases over any sort of file protocol, now Oracle themselves have vast deployments of Oracle over NFS. And Microsoft SQL Server over CIFS, while not so common, has been used for many years with both reasonable performance and high availability by many NetApp customers (although now we would recommend iSCSI with SnapDrive instead of course), and is a configuration that was originally supported by Microsoft only in the context of NetApp storage.
It's very easy to say "that's a stupid idea", but eventually you learn that something that appears to make little sense on it's own can make more sense for a particular environment once all of the issues (technical and non-technical) are considered. There are serious scalability issues with using iSCSI or FCP for VMWare system images (leaving the data volumes aside as a seperate issue that is handled on it's own merits), and the NFS implementation is a very good solution for this apart from improving overall manageability of a large VMWare environment. While I would hestitate before using CIFS for this in any production environment, it may have value in creating a simple and scaleable dev/test solution for a client who then would still use iSCSI or FCP for their production vm images.
regards,
Alan.
----- Original Message ----- From: "Milazzo Giacomo" To: "M. Vaughn Stewart" , "Alan McLachlan" Subject: R: VMWare CIFS driver Date: Thu, 1 Nov 2007 12:13:11 +0100
Hi vmdk images streamed on CIFS? :-) Sorry if I smile but performances will be...terrible!!! That's the reason for the NFS usage available on VMWare.And, after all, VMWare is a RHEL 4.x Linux distribution..to "read" CIFS the service console should have a SAMBA interface on it...heavy role!!! I agree with the license cost of NFS and CIFS together but, after all..iSCSI is free on NetApp. Create an iSCSI LUN and map it to VMWare...best practice! Bye
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Da: owner-toasters@mathworks.com per conto di M. Vaughn Stewart Inviato: lun 29/10/2007 5.45 A: Alan McLachlan Cc: toasters@mathworks.com Oggetto: Re: VMWare CIFS driver
Thanks for bringing this to our attention
V
Alan McLachlan wrote:
Hi Peter,
I can't disagree with anything you have said, particularly re.
failover (see my post that followed).
Incidentally though, it was an internal Network Appliance
whitepaper that alerted me to the possibility of using CIFS for .vmdk files.
See section 9.1.3 on page 58 of TR-3505i.
I understand that being an internal paper I shouldn't be mentioning
it here, and the published version of that paper on A-SIS eliminates the discussion of VMWare, I suspect because support issues haven't been nailed down yet.
Still waiting on feedback from my contact in VMWare, will post when
I hear something.
There are other reasons beside statefulness of CIFS connections to
prefer NFS (performance, etc.), but that's the main issue. I only mentioned it so as not to exclude it as a technical possibility, my followup posts were intended to stop anyone getting too excited about it at this stage. Also even if VMWare were to build it into the kernal, I'd still be pushing clients to pay for an NFS licence instead. The issue here is the cost of the NFS licence, which can be considered high for some Windows-only shops.
regards,
Alan.
----- Original Message ----- From: "Learmonth, Peter" Peter.Learmonth@netapp.com To: "Alan McLachlan" alanmac@technologist.com,
toasters@mathworks.com
Subject: RE: VMWare CIFS driver Date: Sun, 28 Oct 2007 19:10:27 -0700
Hi Alan Would you happen to have a URL instead of a IP address?
Given that this comes from an unidentifiable web site, I highly
doubt
this will get any support from VMware, and I can pretty much
guarantee
that this will get no support from NetApp.
More on the RPM itself... It contains only an object module, which appears to install in the service console Linux, not the VMKernel, although I could be wrong
on
that.
The version on that RPM matches the ESX 3.0.1 COS Linux kernel
version.
Besides, while I think NFS is great for VMware, I think CIFS is horrible. People who have tried it with VMware server or GSX have
had
some surprises when the storage fails over and CIFS drops the connections. It doesn't make any difference whose CIFS server
you're
using. I personally don't think VMware should waste any time
developing
an ESX kernel client.
Thanks anyway.
Peter
-----Original Message----- From: Alan McLachlan [mailto:alanmac@technologist.com] Sent: Sunday, October 28, 2007 4:24 PM To: toasters@mathworks.com Subject: VMWare CIFS driver
Hi,
Find it here:
http://89.105.41.70/sites/esx/Lists/Posts/Post.aspx?ID=1
Enjoy!
regards,
Alan McLachlan
----- Original Message ----- From: "Davies,Matt" MDAVIES@generalatlantic.com To: Peter.Learmonth@netapp.com, alanmac@technologist.com, toasters@mathworks.com Subject: RE: VMware / A-SIS Date: Sun, 28 Oct 2007 21:48:16 -0000
I was about to ask the same question.....
-----Original Message----- From: owner-toasters@mathworks.com owner-toasters@mathworks.com To: Alan McLachlan alanmac@technologist.com; toasters@mathworks.com toasters@mathworks.com Sent: Sun Oct 28 21:09:20 2007 Subject: RE: VMware / A-SIS
Ummmm.... What ESX CIFS driver?
-----Original Message----- From: Alan McLachlan [mailto:alanmac@technologist.com] Sent: Sunday, October 28, 2007 8:26 AM To: toasters@mathworks.com Subject: VMware / A-SIS
Hi Vaughn,
For small environments on a budget where the cost of additional licenses is an issue, you can use RDM's over iSCSI or FCP for both data LUN's _and_ the VM OS images. You still need VMDK pointer files to enable vmotion.
By using RDM's for the VM images you can use lun cloning for R/W snapshots within the same FlexVol, without paying for a FlexClone license and achieve a reasonable level of deduplication without paying
for an A-SIS licence. i.e. create "golden images" as source LUNs then use lun clones for the prod, dev, test and backup images of the VM's.
However, for larger environments using vmdk's on NAS from NFS exports or CIFS shares for the VM images is a far more scalable and manageable
solution as long as you're happy to pay for A-SIS to manage deduplication. I still wouldn't be putting data volumes inside the vmdk's though.
(Yes, you can use CIFS for vmdk's in ESX. Not as ideal as NFS for a whole bunch of reasons, but it works via the VMWare ESX CIFS driver and useful if you have to have CIFS for file server consolidation and don't want to pay for NFS licencing as well).
Either way, storing your application data in either RDM LUN's or as direct NAS shares makes managing snapshots for dev/test copies and online backups of the production data much simpler to manage. Putting data inside vmdk's limits your functionality particularly for backups.
MSCS requires an RDM for the quorum disk, but you can still use a NAS share for the data if your data profile and application characteristics indicate that it makes more sense to do that than use an RDM for the data.
regards,
Alan McLachlan.
-----Original Message----- From: owner-toasters@mathworks.com on behalf of M. Vaughn Stewart Sent: Sun 10/28/2007 8:07 AM 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)
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