Dell Storage with Microsoft Storage Spaces Best Practices Guide

The column count indicates the number of physical disks that Microsoft Storage Spaces stripes data across. The column count has a direct correlation to performance as increasing the column count enables more physical disks to be striped and accessed in parallel during read-and write operations.

You can only configure column count at VD creation by using PowerShell. You cannot set the column count by using the graphical user interface (GUI). Creating a VD in the GUI selects a default column count that may not be optimized for your solution. After a VD is created, the column count cannot be changed. For a VD that uses storage tiers, the column count of the SSD tier and HDD tier must be identical.

Run the following PowerShell command for creating VDs with a specified column count.

New-VirtualDisk -FriendlyName <vdName> -StoragePoolFriendlyName <poolName> 
                                    -ProvisioningType Fixed -ResiliencySettingName <Simple| Mirror| Parity> 
                                    -PhysicalDiskRedundancy <1|2> -NumberOfColumns <#ofColumns>  
                                    -StorageTiers<ssdTierObject, hddTierObject> -StorageTierSizes <ssdTierSize , hddTierSize>
                                 

For example, a new VD is created called exampleVD2 in the storage pool MyPool1. This VD is a two-way mirror. The column count is six for this VD so the NumberOfColumns attribute is set to 6.

New-VirtualDisk -FriendlyName “exampleVD2” -StoragePoolFriendlyName “MyPool1” 
                                    -ProvisioningType Fixed -ResiliencySettingName Mirror -PhysicalDiskRedundancy 1 
                                    –NumberOfColumns 6  –StorageTiers $ssd_tier, $hdd_tier –StorageTierSizes 100GB,15TB
                                 

When sizing the column count of a VD, consider the following.

For mirrored VDs:

Without enclosure awareness

With enclosure awareness

For dual parity VDs:

Without enclosure awareness

With enclosure awareness

For example, if you have three DSMS 3060e storage enclosures each with 12 x SSDs and 48 x HDDs, and decide to create two storage pools—MyPool1 and MyPool2, this is how you would calculate the column counts for the VDs in different situations.