Correct disk sector size selection

[madmongoose]

Hello, StarWind!

Such a topic did not find.
Please tell me how to do it right.

At the RAID controller level, the logical partition was created with a disk block size of 512 Bytes. In the operating system, I formatted the partition in 64K. StarWind HA Devices was created with 512 Bytes (like a RAID controller). Actually the question is, how do I format the Cluster Shared Volume? Can I format it in 64K for Hyper-V vm files, and storage?

RAID 512 B
OS Partition 64K
StarWind Flat HA Disk 512 Bytes
CSV - ?

Best Regards.

[Boris (staff)]

madmongoose,

If you are going to use your StarWind HA images with Hyper-V, create them with 4k sector size. Sector size 512 is intended for ESXi datastores.
I would recommend selecting the Default value for the Allocation Unit Size in the Disk Management console for StarWind disks connected via iSCSI.

[madmongoose]

Boris, I wanted to do 4K for Starwind. But my disks are made in 512. Will there be any problems? I was guided by this article (https://knowledgebase.starwindsoftware. ... lock-size/).
it says

4096 Logical ↦ 512 Physical

Using 4096 logical block size on 512 may slightly reduce the overall performance since in that case all the data are generally processed in 512-byte segments, however, most of operating systems are using 4096 block size.

1

photo_2018-02-09_13-36-03.jpg (17.65 KiB) Viewed 9213 times

Make it like this?
RAID 512B
File system 4K or 64K
Starwind 4K ????
СSV 4K

[Boris (staff)]

The best way is getting hard drives that have the 4k block size, which is not your case at the moment.
You can keep StarWind disks as 4k block size then.
Let's imagine a couple of variants:
Variant 1.
- RAID 512B
- File system 4K/64K
- Starwind 4K
- СSV 4K
Seems pretty logical, though the underlying disk has smaller block size.
Variant 1.
- RAID 512B
- File system 512
- Starwind 512
- СSV 512
This might look even better. Until you learn that Microsoft itself has generated a complete mess with this: for VHD files the block size is 512, while for VHDX files it is - boom! - 4K. You will most likely use VHDX files for your VMs, so I do not believe you will be able to completely eliminate block size difference unless you change the hard drives for 4K ones.
Synthetic tests for variant 1 show nice performance results, so I would select it, if changing the disks is not an option.

[madmongoose]

Boris, thank you very much!
I'm stay on variant 1)

[Boris (staff)]

Good. If any other questions arise, post them at our forum.