Virtualization! Virtualization–what you should consider when going virtual. Some storage best practices for Hyper-V
These days it has become trendy to talk about Virtualization. Virtualization has its virtues – however,you also
need to study and plan carefully the workloads that you want to virtualize. Since database hosting is getting
virtualized and databases by their very nature are very I/O intensive there are a myriad of things you need
to understand when virtualizing database workloads.
So, before you virtualize a workload you should have an understanding of what that workload looks like on
a physical machine first and part of that understanding involves storage interaction. I/O intensive
workloads like SQL require some planning. SQL even has a tool that can be used to simulate workloads
on storage, which you can find in this link:=
Some of the other relevant links to Virtualizing SQL are here:
OK. Now coming to some of the salient points, SQL virtualization needs careful consideration of the
storage systems you are using and its I/O characteristics. Some of the main considerations are as below.
- Use fixed-size disks. Defrag your volumes before creating the VHDs
- Use SCSI Virtual adapters for data disks attached to Virtual Machines
- Use pass-through disks for the best performance and for LUNs > 2TB
- Do *NOT* use snapshots in a production environment
- Use high speed storage configurations
- High speed SATA\SAS drives (10,000 rpm or greater)
- Use drives that support command queued I/O.
- Use RAID 0+1 configurations with as many disks as feasible in
the RAID configuration to distribute I/O
- Use MPIO configurations for storage
- Use the highest speed NICs for iSCSI storage
- Do NOT store system files (e.g. pagefile) on storage used by Hyper-V
- Test storage I/O configurations before deploying Virtual Machines
- Follow operating system Performance Tuning guidelines
- If you are running Anti-Virus software in the Parent partition, exclude either Hyper-V processes (vmms.exe or vmwp.exe) for Hyper-V file types (.vhd, .avhd, .vfd,.vsv, .bin and .xml )
- When using CSV LUNS, place virtual machine operating system files and data on different volumes
- And last (but not the least) consult your storage vendor.
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