Disk Alignment EVA 6100, ESX 3.5, Windows 2003 + SQL2005

[Douglas Spooner]

Hello

We have been quite happily using the following

EVA6100, ESX 3.5u4, Windows 2003 R2 and SQL 2005.

I've seen quite a few posts around several forums on the subject of disk alignment that can help to further improve disk performance.

I was looking for some advice as alot of posts dont talk about all 3 technoligies together.

vDisks on EVA 6100 are set to Vraid 5

VMFS 1 (Block Size 1MB) - Contains Windows 2003 OS
VMFS 2 (Block Size 2MB) - Contains SQL Binaries and DB's
VMFS 3 (Block Size 3MB) - Contains SQL Backups

VMDK1 on VMFS1 24GB OS Install + Page file
VMDK2 on VMFS2 500GB SQL Binaries and SQL Data
VMDK3 on VMFS2 1024GB SQL Backups

We have been formating the disks in windows as the default option.

Would there be any benefit with the above by formating the size different in Windows for the SQL disks and what would they be set to?

Any comments or further reading would be most appreciated.

Doug

[Prokopets]

First of all, raid5 is not a good idea if performance is an option. Use raid1. Guys from VMWare do not recommend to virtualize SQL servers and application like it because of overhead. You gonna loose quite big part of server performance on it.
As for disk configuration i can say that it's a good idea (in your configuration and tasks) to allocate LUN's and logical disks keeping this formula in mind: One task -> one LUN, one logical drive.
You can also read SQL Server best practices: http://msdn.microsoft.com/en-us/sqlserver/bb671432.aspx
and EVA best practices: ftp://ftp.compaq.com/pub/products/storageworks/whitepapers/5982-9140EN.pdf

[Uwe Zessin]

The EVA has a pretty competent VRAID-5 implementation and many of our customers use it for their databases with success.

Partition alignment was once suggested for some special workloads on VRAID-5 vdisks on EVA-3000 and EVA-5000 arrays, but it was claimed that the limitation does not exist on later EVA arrays - should not hurt, though.

If you create a VMFS datastore through the VI-Client, the (VMFS) partition is automatically aligned on 128 blocks. You can certainly test whether it helps to align partions in VMDKs or RDMs - will you let us know what you find out?

I've once read that a 64KBytes NTFS cluster size was suggested for MSSQL servers - maybe that is more efficient.


> Guys from VMWare do not recommend to virtualize SQL servers

Maybe those guys should talk with the authors of VMware's own documents:


VMTR1007 - SQL Server Performance in a VMware Infrastructure 3 Environment
http://www.vmware.com/resources/techresources/1007

""This performance study clearly demonstrates that VMware Infrastructure 3 provides an excellent production-ready virtualization platform for customers looking to deploy Microsoft SQL Server inside virtual machines.""


VMTR1081 - SQL Server Workload Consolidation
http://www.vmware.com/resources/techresources/1081

""... With improvements in virtualization technology and hardware, even servers running large database workloads run well in virtual machines. Servers running Microsoft's SQL Server, among the top database server platforms in the industry today, are no exception.""

[Prokopets]

Uwe: i'm not going to fight against vmware's marketing documents :). I know what was told to me unofficially, and of course this information could be little different from official site. As for EVA and raid5: i just can say that it's all about how the database will be loaded. Maybe, it can be even virtualized.