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Pure1 Support Portal

File Systems

Overview

Both Windows Server New Technology File System (NTFS) and the Resilient File System (ReFS) are supported with Pure Storage FlashArray. Windows Server 2008 R2, 2008 R2 (Service Pack 1), 2012, 2012 R2 and 2016 by default use a 1024 MB starting offset. 

Pure Storage uses a 512-byte geometry on the FlashArray and, as such, there will never be a block alignment issue. To determine block alignment use the StartingOffset from Win32_DiskPartition and divide by the Blocksize from Win32_Volume. The resulting value should be an integer value.

StartingOffset / Blocksize = Integer Value

Example using the below values from three FlashArray volumes:

Disk #0     --  1048576 / 4096 = 256
Disk #1, #2 -- 34603008 / 4096 = 8448 

To check the StartingOffset of a Windows Server host use the following Windows PowerShell:

Get-WmiObject -Class Win32_DiskPartition -ComputerName $env:COMPUTERNAME | select Name, NumberOfBlocks, Size, StartingOffset, Blocksize | Format-Table -AutoSize

Name                  NumberOfBlocks          Size StartingOffset Blocksize
----                  --------------          ---- -------------- ---------
Disk #0, Partition #0        1024000     524288000        1048576       512
Disk #0, Partition #1      313544704  160534888448      525336576       512
Disk #1, Partition #0     2147414016 1099475976192       34603008       512
Disk #2, Partition #0     2147414016 1099475976192       34603008       512

The Blocksize output above represents the physical block size at which the Pure Storage FlashArray is writing data. Disk #0 is a SAN boot volume for C:\ and Disk #1 and #2 are the ReFS and NTFS volumes respectively.

Get-WmiObject -Class Win32_Volume -ComputerName $env:COMPUTERNAME | Select BlockSize, Name, FileSystem | Format-Table -AutoSize

BlockSize Name                                              FileSystem
--------- ----                                              ----------
     4096 \\?\Volume{715e64e7-0000-0000-0000-100000000000}\ NTFS      
     4096 D:\                                               ReFS      
     4096 E:\                                               NTFS      
     4096 C:\                                               NTFS

The BlockSize (cluster size or allocation unit size) output above represents the logical block size that is used for the formatting of the file system, ReFS or NTFS.

 

NTFS (New Technology File System)

NTFS allows formatting a drive with a wide range of cluster sizes (allocation unit size). We do not have any specific recommendations outside of using an 64K for Microsoft SQL Server workloads. See the SQL Server > Quick Reference: Best Practices for more details.

 

ReFS (Resilient File System)

ReFS supports both 4K and 64K cluster (allocation unit size) sizes. 4K is the recommended cluster size for most deployments, but 64K clusters are appropriate for large, sequential IO workloads. We do not have any specific recommendations outside of using an 64K for Microsoft SQL Server workloads. See the SQL Server > Quick Reference: Best Practices for more details.