Database Reference
In-Depth Information
When you are defining your SQL Server Database Service Catalog, group your
VMs not only by CPU and Memory requirements but also Storage IO
requirements. The Storage IO requirements can then drive your storage policy
design, at both the vSphere and physical storage layer, and the relevant data store
clusters that need to be supported.
vSphere Storage Multipathing
Each block storage device (FC, FCoE, iSCSI, and so on) on the VMware Hardware
Compatibility List (HCL,
http://www.vmware.com/go/hcl
)
leverages VMware Native
Multipathing (NMP) and will have a Storage Array Type Plugin (SATP) and a default
Path Selection Policy (PSP). The default SATP and PSP for your storage device will
depend on the vendor, and in some cases it will use a VMware generic SATP, such as
VMW_DEFAULT_AA. The PSPs that are part of the built-in VMware NMP are
referred to as initiator-side load-balancing or path selection policies. This is because
all path selection decisions are made from the host only.
There are three built-in PSPs to choose from: VMW_PSP_MRU, VMW_PSP_FIXED,
and VMW_PSP_RR. To get the best performance out of your storage and provide the
highest performance and lowest latency to SQL Server, we recommend you use the
VMware Round Robin PSP (VMW_PSP_RR) where possible. Your storage vendor
may have a particular best practice with regard to advanced options when using Round
Robin that you should follow.
Note
For vSphere 5.1 and below, VMW_PSP_FIXED and VMW_PSP_MRU are
the only valid options when using SQL AlwaysOn Failover Clustering.
When using SQL AlwaysOn Availability Groups, you are free to choose
any path selection policy you like because it does not require shared disk
failover clustering or a shared SCSI bus configuration. vSphere 5.5
introduced support for VMW_PSP_RR for SQL AlwaysOn Failover
Clustering.
Tip
For a full list of all the supported storage devices and their associated default
SATP and PSPs, refer to the VMware Storage Compatibility Guide
(
https://www.vmware.com/resources/compatibility/san_reports.php?
VMware KB 1011340.
