Hyper - V Pass through disk vs VHD Fix

[Rozzer]

Hi All,

 

I am in the process of setting up my virtual enviroment again with a new SAN and wanted to know if I am better of using VHD files or pass thru disks? I have setup VHD disks for SQL and exchange and student / staff data. Am I better of using VHD?

 

Thanks

 

Ross

[adrian_costea]

You can read this article then make a choise. You get performance by using pass-throught disks, but you loose an important feature, portability.

 

Hyper-V pass-through disk performance vs. fixed size VHD files and dynamic VHD files in Windows Server 2008 R2 « Clustering For Mere Mortals

[sidewinder]

I ran with a pass-thru disk for a while but decided to change purely due to the portability - it became a big issue if I had to do anything with that host.

 

Performance wise, I have seen absolutely no degradation whatsoever - this is with about 100GB of user shares. I would recommend VHD

[british_government]

Just a note on SQL and hyper-v.

 

For large database systems the ideal setup is 4 physical disks for a sql server, although 2 is good and 3 is most common. The 4 physicals disks are used one each for OS, Transaction Log, Master DB and Application DB. We currently have issues with our Hyper-V sims server running from a SAN, as no matter how many VHD's we create they could all sit on the same physical disk on the SAN, or be spread across disks on the SAN shared by other disk intensive servers.

 

Anyway, the point im slowly making is if setting up a SQL server in Hyper-V, I would use VHD's but split onto different physical disks on the hyper-v server.