The task is to change the Exchange Server DAG witness server to another server. Why…
The allocation unit size or named block size of a partition is vital for the systems. Think about the system performance. A partition is default formatted with a standard 4KB allocation unit size. It does not mean that it’s the best practice. Microsoft recommends that partitions have a 64KB allocation unit size for SQL Servers and Exchange Servers. In this article, you will learn how to find the partitions allocation unit size with PowerShell.
Information about the allocation unit size
Before we start to find the partition allocation unit size or named block size. It’s good to know the difference between disk, volume, and partition. A disk does have one volume, and the volume can be split into multiple partitions.
For example, you have a 100GB disk. It means that the volume is 100GB. You can split the 100GB volume into partitions of the size 20GB, 20GB, and 60GB. Thus, you will have one or more partitions. In every partition, you can set a different allocation unit size.
The allocation unit size can be set differently in every partition.
Get allocation unit size with PowerShell
We like to get the allocation unit size on all the partitions of the Exchange Server EX01. We are going to run the Get-CimInstance cmdlet. Run PowerShell as administrator.
PS C:\> Get-CimInstance -ClassName Win32_Volume | Select-Object Label, BlockSize | Format-Table -AutoSize Label BlockSize ----- --------- System 4096 DB01 Data 65536 DB01 Logs 65536 DB02 Data 65536 DB02 Logs 65536 DB03 Data 65536 DB03 Logs 65536 DB04 Data 65536 DB04 Logs 65536 OSDisk 4096
BlockSize 65536 = 64KB allocation unit size. BlockSize 4096 = 4KB allocation unit size.
As a result, we have 10 partitions on the EX01 server, an explanation of every partition:
- System partition is hidden. The partition is created by default when you install an Operating System (OS).
- DB01/DB02/DB03/DB04 Data and Logs partitions are the Exchange database data and logs.
- OSDisk partition is the Operating System (OS).
To summarize, you learned how to get the allocation unit size with PowerShell. If you have SQL or Exchange Server, make sure that the block size is 64KB. Microsoft did write an excellent document about the Get-CimInstance cmdlet.
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