VMware – VMFS Notes

>These are the following notes while might be helpful for VMware Enthusiastic.

Note :

1) VMFS can support LUNs with max size of 2TB, Suppose if we need 4 or 6 TB luns then we can distribute like 2*2TB.
2) Up to 100 non-IO-intensive VMs can share a single VMFS volume with acceptable performance.
3) No more than 255 files per VMFS partition.
4) Up to 2TB limit per physical extent of a VMFS volume. There are 32 extent we can add on a VMFS filesytem.

What do you mean by extent here.Let me eloborate it –

VMFS filesytem works on the LVM concent like LVM support ‘8e’ filesytem the same way VMFS filesystem support ‘fb’ filesytem. The extent
here represents the block of disk as it was referred in disk concept.

5) Allows access by multiple ESX Servers at the same time by implementing per-file locking. SCSI Reservations are only implemented when LUN meta data is updated (e.g. file name change, file size change, etc.)
6) Add or delete an ESX Server from a VMware VMFS volume without disrupting other ESX Server hosts just because of shared disk storage as only CPU and Memory stats are associated with ESX server only.
7) LVM allows for adaptive block sizing and addressing for growing files allows you to increase a VMFS volume on the fly (by spanning multiple VMFS volumes)
8)With ESX/ESXi4 VMFS volumes also can be expanded using LUN expansion
9)Optimize your virtual machine I/O with adjustable volume, disk, file and block sizes.
10)Recover virtual machines faster and more reliably in the event of server failure with Distributed journaling.
11) VMFS file size ( Block size)
1 MB = 256 GB
2 MB = 512 GB
4 MB = 1024 GB
8 GB = 2048 GB
(Max vmdk filesize on VMFS partition is 2TB.)

12) Recommended limit of 16 ESX servers per VMFS volume,based on limitations of a VirtualCenter-managed ESX setup.

a) A VMFS volumn can be shared with upto 32 ESX Servers.
b) Recommended maximum of 32 IO-intensive VMs sharing a VMFS volume.


3 thoughts on “VMware – VMFS Notes

  1. Idalia November 18, 2011 at 12:57 am Reply

    That’s not just logic. That’s rellay sensible.

    • Kalyn December 1, 2011 at 10:07 am Reply

      This does look promising. I’ll keep cmonig back for more.

    • Emma December 3, 2011 at 6:29 am Reply

      You really saved my skin with this inoftrmaion. Thanks!

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