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2019/10/09

Remove Node

Remove Node and the impact on the vDisk 


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The following Demo are performed in a S2D test environment with 6 Cluster Nodes.

The Windows Version is important in this Demo, the Extent size in this Demo is 1GB
(Note: the vNext will use a different Extent size) 

Each Node have 5 SSDs used for the Storage Pool.

If you dont have access to Physical Lab Servers you can use WSLab and get some more information from the Scenarios

Task:
Remove Node from Cluster. Retire the Disk before the Node is removed.

Columns:
Know you Columns count and free Disk space, before you start to remove Disk/Nodes. 

6x5=30 Physical Disk
All vDisks are created with the default maximum columns count of 8 and 3 way Mirror

3x8=24 Disk used for every Extents
When we remove a Cluster Node we go from 30 Physical disk to 25 Physical Disk so the Columns of 8 (Need 24 Disk) will not impact the Performance if we have free space on the remaining Physical Disk.

The Test vDisk1 was create with the PowerShell command:
New-Volume -StoragePoolFriendlyName S2D* -FriendlyName vDisk1 -FileSystem CSVFS_ReFS -ProvisioningType Fixed -Size 200GB -Verbose

Note: If you need to remove the vDisk
Remove-VirtualDisk vDisk1



Before we remote the Node we create a new vDisk to follow the Extents 



PowerShell:
New-Volume -StoragePoolFriendlyName S2D* -FriendlyName vDisk4 -FileSystem CSVFS_ReFS -ProvisioningType Fixed -Size 200GB -Verbose
Get-VirtualDisk "vDisk1"
$VirtualDisk4 = Get-VirtualDisk "vDisk4"
$Extents4 = Get-VirtualDisk "vDisk4" | Get-PhysicalExtent | Where VirtualDiskUniqueId -Eq $VirtualDisk4.UniqueId
$Extents4 | Group OperationalStatus -NoElement
$Extents4 | Group CopyNumber -NoElement
$Extents4 | Group Size -NoElement

# Show the first Columns of Extents and Copyes (8x3=24)
Get-VirtualDisk "vDisk4" | Get-PhysicalExtent | Select-Object -First 24 

Create a 200 GB vDisk (With the size information from below we need 200 Extents to create a 200GB vDisk)
Show the total of Extents (3 way Mirror then we have 3x200 = 600 Extents)
Show each copy of the Extents (200 in copy 0, 200 in copy 1 and 200 in copy 2)
The default will be 0,1,2 in a 3 way Mirror.
When we start to remove Disk/Node we will see copy 3,4 more information below
Show the size of one of the Extents (1073741824 Bytes = 1024MB or 1GB)

The Cluster Node S047023 have some problems with one Physical Disk (The node only list 4 of the 5 Disks installed and need to be replaced)

Node S047023 only list the 4 of 5 diske. All 4 Disk are listed as Retired

After the Physical Disk have 0% of the Extents (Only 4 of 5 listed do to Hardware Problem and the Node need to be replaced)

Now it is time to remove the Node S047023 from the Cluster

Show the Extents 600 Active Extents before retire the disk
List the Extents in each Copy
List the Storage job when the DIsks are retired
List the Copy number in the process of the retire