Wednesday, January 21, 2015

Understanding number of columns in Storage Pools and Storage Spaces

In this post, I'd like to talk about some PowerShell cmdlets related to configure number of columns of storage pools and storage spaces (virtual disks). One of my previous post, I talked about creating storage pool by PowerShell. How about the number of columns setting? I'm going to do some demonstrations to show these settings.

Lab environment
  • 1 virtual machine with 9 virtual disks
  • 1 Storage Pool named Pool1
Basically, the number of columns settings for "Simple", "Mirror" and "Parity" on a storage pool is "Auto". We can perform "Get-ResiliencySetting" to verify it.

By default, the maximum number of columns is 8 if the setting is using "Auto". We can perform "Set-ResiliencySetting -NumberOfColumnsDefault" to modify to higher or lower number of columns settings of this Storage Pool.

In my lab, I changed number of columns setting to 1 for Mirror storage layout of Pool1. When I create a new storage space (virtual disk) with Mirror storage layout under Pool1. The data is only under 1 physical disk and 1 copied data is on another physical disk. It doesn't expand to other physical disks because we configured number of columns setting to 1.

Then, I created a storage space (virtual disk) named vdisk1 and then perform "Get-VirtualDisk" to verify the result.

When we create a new storage space (virtual disk), we can add the parameter "NumberOfColumns" into "New-VirtualDisk" to override the number of columns setting of the pool, Pool1.

Changing the number of columns, it can improve the read and write performance of virtual disks.
For more information:

This posting is provided “AS IS” with no warranties, and confers no rights!

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