NX4, NFS, Virtualized Exchange Support

Question

I have posted this in the Celerra support forums, and it was suggested that I post it here as well, as the root source of my situation is that Microsoft does not support Exchange VM's on NFS datastores in VMWare. Any help, options, and opinions welcomed.... I have an existing NX4, serving CIFS to Windows Clients (Significant use of CIFS in the environment) and NFS to a VMware environment. (about 30 guests across 3 hosts) The current NX4 design has 2 cge ports configured with LACP supporting CIFS in one VLAN and the other 2 cge ports configured with LACP supporting NFS in a different VLAN. All switch ports are access ports. Jumbo Frames are enabled on the NFS ports. I now have to introduce iSCSI into the picture, as the customer is virtualizing Exchange, and NFS datastores with Exchange VM's are not supported. I have available network ports on the ESX side to dedicate to iSCSI traffic, so I can dedicate them to vmkernal ports, attach the ESXi software iSCSI initiator, enable MPIO etc etc, so no problem there. My challenge is how to best introduce iSCSI networking from the NX4 side. Ideally, I'd have (2) NX4 network ports not configured in a LACP to do end to end native MPIO. In order to do that, I would have to move my NFS traffic over to the CIFS LACP, change the CIFS switch ports to a TRUNK port, and have CIFS and NFS traffic traverse the same NX4 physical links.. Clearly, this will push the utilization if these network links up, and I am not sure of the impact of enabling JUMBO frames on these ports will have on CIFS traffic that is not using JUMBO frames. So not ideal The other option for me would be to combine NFS and iSCSI traffic on the current NFS LACP connection. I would add an iSCSI target with multiple IP's, and still use VMWare native NMP on the ESX side, but it would be LACP on the NX4 side, so again not ideal.. But no JUMBO frame issues, and I think I would have a better balance of network. Are there other options that I should consider? What would be the preferred option in your opinion? Second question, on the NX4, iSCSI being served from the datamovers, with either approach, can the iSCSI connections reside in the same subnet or is it required that they be in seperate subnets or does it not matter? Thanks Jim

duckew · Answer

Jim,You are correct that Microsoft does not support Exchange VMs on NFS datastores.We do have Microsoft Exchange 2010 on VMware Best Practices Guidebelow is the link check it out and see if that helpshttps://community.emc.com/docs/DOC-11812Also found this WhitepaperEMC Tiered Storage for Microsoft Exchange 2010 Enabled by Celerra Unified Storagehttp://www.emc.com/collateral/solutions/white-papers/h7203-tiered-storage-exchange-celerra-wp.pdf

ltpolaris · Answer

Thanks for the links to the White papers. Unfortunately, neither address my questions. It is also interesting that the h7203 white paper tested Exchange on NFS based VMware datastores, and made no mention that it was not supported by Microsoft..

It does mention CIFS is not supported by Hyper-V

I would think the Microsoft support stance should be stated in the white paper

Thanks, Jim

DButch1 · Answer

Actually, Exchange database stores are not supported on file shares whether or not the Exchange Server is running virtualized. Courtesy of Jim Cordes, who answered this on the Microsoft Specialist Community distribution:

http://technet.microsoft.com/en-us/library/cc794548(EXCHG.80).aspx

"The storage that is used by the Exchange Server guest machine for the storage of Exchange data (for example, mailbox databases or hub transport queues) can be virtual storage of a fixed size (for example, fixed virtual hard drives [VHD] in a Hyper-V environment), SCSI pass-through storage, or Internet SCSI (iSCSI) storage. Pass-through storage is storage that is configured at the host level and that is dedicated to one guest machine. All storage that is used by an Exchange guest machine for the storage of Exchange data must be block-level storage. Exchange 2010 does not support using network attached storage (NAS) volumes. NAS storage that is presented to the guest as block-level storage by using the hypervisor is not supported. Pass-through volumes must be presented as block-level storage to the hardware virtualization software. This is because Exchange 2010 does not support using network attached storage (NAS) volumes. The following virtual disk requirements apply to volumes that are used to store Exchange data."

You may interpret this to mean that CIFS and NFS are NOT supported. If you are truly worried about support, use iSCSI into the guest via the Microsoft iSCSI initiator. However — since SVVP was launched several years ago, I have never heard a whisper of complaint by PSS that a customer was using NFS rather than iSCSI…

Additional links.

http://www.vmware.com/support/policies/ms_support_statement.html

http://support.microsoft.com/kb/897615

ltpolaris · Answer

Thank you DButch..

The customer does not want to be put in a position where they have a configuration that is formally not supported, so deploying Exchange on NFS datastores will not be an option for us..

I interpret this..

"NAS storage that is presented to the guest as block-level storage by using the hypervisor is not supported." as NFS based datastores.

Our strategy is to do iSCSI out of the NX4 as the methodology to have a configuration that is fully supported, and then my challenge is how to best do that given the current configuration of the device. (refer to the original posting)

Any insight into that greatly appreciated

Jim

DButch1 · Answer

Most of the KB articles I've found on this topic have been ambiguous - they talk about how to configure block storage for Exchange database files, but simply ignore the topic of shares. (Lack of support through lack of discussion??) Kudos to Jim for finding something mostly unambiguous.

IIRC (it's been a while) prior versions of Exchange wouldn't let you put an Exchange database out on a share at all through the normal management tools.

That statement ""NAS storage that is presented to the guest as block-level storage by using the hypervisor is not supported." is a bit odd - Celerra (and a number of our competitors) create a file on their internal file system and present it as an iSCSI LUN. But doesn't go through an intermediate NAS protocol or get translated by the hyper-visor, so presumably this restriction doesn't apply to iSCSI presented by the NX or NS head.

/B

ltpolaris · Answer

DButch,

We are interpreting this statement

"NAS storage that is presented to the guest as block-level storage by using the hypervisor is not supported." as not applying to iSCSI storage presented out of a datamover, as you suggest..

The hypervisor is not translating it.. To the hypervisor, it is native block storage.

The question still remains, how to best implement iSCSI storage out of an NX4 with an existing NFS and CIFS environment already present as posed in my original post

Thanks, Jim

Microsoft

Microsoft Exchange 2010 on VMware Best Practices Guide

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