Proper Configuration for Hyper V and file server/sql server.

Question

We have a PE640 with 2 SSD SATA for the physical OS and then 6 1.6TB SSD SAS drives in one large RAID 10 virtual disk to house the Hyper V vhdx's in Windows 2019 Server.  What would be the best configuration for the VM's vhdx's for OS, File Server Storage and SQL server: A: Leave the default allocation unit size on the physical server to 4k on the single large RAID 10 virtual disk? Then build the OS and File Server vhdx's to 4k allocation unit size and the sql server vhdx's to 4k allocation unit size? B: Leave the default allocation unit size on the physical server to 4k on the single large RAID 10 virtual disk? Then build the OS and File Server vhdx's to 4k allocation unit size and the sql server vhdx's to 64k allocation unit size? C: Set the allocation unit size on the physical server to 64k on the single large RAID 10 virtual disk? Then build the OS and File Server vhdx's to 4k allocation unit size and the sql server vhdx's to 64k allocation unit size? Set the allocation unit size on the physical server to 64k on the single large RAID 10 virtual disk? Then build the OS and File Server vhdx's to 64k allocation unit size and the sql server vhdx's to 64k allocation unit size? E: Create two disk partitions on the physical server splitting the single large RAID 10 virtual disk at the OS level.  One with a 4k allocation unit size and one with a 64k allocation unit size? Then build the OS and File Server vhdx's to 4k allocation unit size and place them on the physical partition that has the 4k allocation unit size and then build sql server vhdx's with 64k allocation unit size and store them on the physical partition that has the 64k allocation unit size? Option E sounds best to me but it may not be and there may be other options I don't have listed.  - The 4k side would house the VM OS vhdx's and the VM File Server vhdx's that has a large number of files smaller than 64k. - The 64k side would house the VM SQL vhds's for the data, tempdb and trans log. Any guidance would be appreciated. Thanks...

DELL-Marco B · Answer

Hello,

what is the difference between choice A and B?

For me too option E is the best, it is more easy working with partitions at the OS level. Anyway I don't think there will be a huge difference between the choice in terms of performance.

I don't see other solutions i can propose to you.

Let's see also what the community says.

Thanks

Marco

SMCKY · Answer

Option A and B has one large 4k volume. Then option A has both the OS and SQL Partitions at 4K and Option B has the OS at 4K and SQL at 64K.

Option E has the SQL files 64K all the way to hardware and OS's 4K all the way to hardware. I know the drive level is 512b technically with these drives but my thought is that Option E manages IO amplification the best and should keep the SQL Extents, VM VHDX, and Physical Drive all in alignment to the physical disk.

DELL-Marco B · Answer

Unfortunately we don't have the ability to benchmark, but theoretically it should keep everything aligned.

Obviously there are many different opinions about it, there is no official best practice.

Thanks

Marco

PowerEdge HDD/SCSI/RAID

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