VMFS 6

New vSphere 6 .5  has been release with New File system after VMFS 5 released in 2011. Good news is that VMFS6 supports 512 Devices and 2048 Paths. In previous versions the limit was 256 devices and 1024 paths and some customers were hitting this limit in their cluster. Especially when RDMs are used or people have a limited number of VMs per datastore, or maybe 8 paths to each device are used it becomes easy to hit those limits. Hopefully with 6.5 that will not happen anytime soon.

Automatic Space Reclamation is the next feature that many of customers/administrators have been waiting for. basically this is based on VAAI Unmap which has been around for a while and allows you to unmap previously used blocks. using Unmap storage capacity is reclaimed and released to the array so that when needed other volumes can use those blocks. Previously we need to run Unmap command to reclaim  the blocks, now this has been integrated in the UI and can be turned on or off from GUI.

SESparse will be the snapshot format supported on VMFS6, vSphere will not be supporting VMFSparse snapshot format in VMFS6, it will continue to be supported on VMFS5. Both VMFS 6 and VMFS 5 can co-exist but there is no straight forward  upgrade from VMFS5 to VMFS6. After you upgrade your ESXi hosts to version 6.5, you can continue using any existing VMFS5 datastores. To take advantage of VMFS6 features, create a VMFS6 datastore and migrate virtual machines from the VMFS5 datastore to VMFS6 datastore. You cannot upgrade the VMFS5 datastore to VMFS6. right now SE Sparse is used primarily for View and for LUNs larger than 2TB. with VMFS 6 the default will be SE Sparse.

Comparison is as below:

Features and Functionalities VMFS5 VMFS6
Access for ESXi 6.5 hosts Yes Yes
Access for ESXi hosts version 6.0 and earlier Yes No
Datastores per Host 1024 1024
512n storage devices Yes (default) Yes
512e storage devices Yes. Not supported on local 512e devices. Yes (default)
Automatic space reclamation No Yes
Manual space reclamation through the esxcli command. Yes Yes
Space reclamation form guest OS Limited Yes
GPT storage device partitioning Yes Yes
MBR storage device partitioning Yes

For a VMFS5 data store that has been previously upgraded from VMFS3.

No
Storage devices greater than 2 TB for each VMFS extent Yes Yes
Support for virtual machines with large capacity virtual disks, or disks greater than 2 TB Yes Yes
Support of small files of 1 KB Yes Yes
Default use of ATS-only locking mechanisms on storage devices that support ATS. Yes Yes
Block size Standard 1 MB Standard 1 MB
Default snapshots VMFSsparse for virtual disks smaller than 2 TB.

SEsparse for virtual disks larger than 2 TB.

SEsparse
Virtual disk emulation type 512n 512n
vMotion Yes Yes
Storage vMotion across different datastore types Yes Yes
High Availability and Fault Tolerance Yes Yes
DRS and Storage DRS Yes Yes
RDM Yes Yes

Happy Learning 🙂

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s