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HI

i have ProLiant DL380 Gen10 hyperv server core with 2 sata drive of 1tb which is the hyper v host. so i did atatched 5TB of storage from the SAN over iscsi. then configured the VM where the VHDX are on the iscsi attached stoarge.

is this a good setup or should l be using the local sata drive on the server core host as the c drive for those vm and add another VHD storage space from the SAN ???

is there any guide line ??

please advise

thanks

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Like a lot of these style questions, the answer is “it depends”.

Is it a valid setup? Yes, absolutely.

Will it work? Yes.

Does it provide what you need? well, only you can answer that.

The issues with iSCSI are that the SAN itself is often a single point of failure. Lose the SAN, the VM’s go down no matter how many hosts you have.

iSCSI is also often not setup as best practice. It’s often on a regular user network than over a dedicated storage network. iSCSI is often always 1Gbit which may well lead to latency and so be slower than local disk.

Going back to your question - It depends.

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If it’s a true SAN with a dedicated storage network I’d say you’re fine. Local storage on hardware RAID is always better, faster, and more reliable though.

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I concur with what the others have said.

My view is local storage over SAN 99% of the time.

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I’ve done almost the same exact thing at my previous job, only difference was we used a NAS device. My previous manager designed it that way for a few reasons I can think of. But it worked fine. Only small issue they had was when the iscsi connection had to be refreshed after a small power outage.

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If they accessed data over iSCSI it wasn’t a NAS. It was a SAN.

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What is the make and model of the SAN, and it’s disk configuration?

My SANs have been Dell EqualLogic and now HPE Nimble. I guarantee that they are faster than a pair of local SATA drives in basically every measure including read latency, write latency, and random IOPS. This is true even over a single gigabit connection.

A pair of local SATA disks can support 0-4 Windows VMs or so, depending on what the VMs are doing. Remember that your local desktop or laptop probably has better local than your Hyper-V host.

For my Hyper-V hosts that are in a datacenter with access to SAN storage, I have a pair of local disks to boot Hyper-V, and then all VMs are on iSCSI storage.

For my Hyper-V hosts without SAN access, they have local SSD to store VMs.

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Nimble do some pretty slick caching so will almost certainly always be faster.

I’ve always wanted to setup a server with local NVME and do some speed tests between a single NVM and remote FC connected SAN to see if I can get local disk to be faster than SAN even over FC :slight_smile:

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Cool, I was just referring to the QNAP NAS appliance.

@garydwilliams

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It’s still a SAN if you’re using iSCSI.

SAN = Block Protocol

iSCSI is a block protocol.

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It’s a very bad setup actually. Your storage server is SPOF (Single Point of Failure) and you need at least two of those to run them in HA mode. + running VMs from local disks is faster. + Hyper-V has very poor iSCSI support (iSCSI initiator was written back in 2006 so it has no RDMA support and can’t handle multiple CPU cores efficiently), so SMB3 is preferred.

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The current setup will work fine, but on the other hand, it would be great to consider using replicated local storage since in the current scenario - a definite single point of failure.

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