Extending a VMFS Volume to Use New LUN Space After Expansion

[sasser]

Hello,

I have VI3.5. I have expand my LUN Space from 40 GB to 150 GB. On this Storage stores all VMs. In the Disk Layout: primary Partition have 40 GB and 110 GB free. How can I expand the Storage to 150 GB??? When I select "add extent..." this warning comes "The current disk layout will destroyed. all files and data will be lost permanently". Is this way wrong? I need this data ;-). Only the Kb 1752 I have found to my problem and the Kb is only for 2.x?!

See my attached file.

Please help, Thanks and bye.

[TomHowarth]

The warning you are seeing is actually referring to the space you are adding via extents. The data on the space being added will be lost, not the data currently in your VMFS Datastore currently.

however it is not really considered good practice to use extents it would be better to either create a nrew VMFS partition, or migrate the VM/s that are hosted on the current partition to a VMFS partition with space and then trash the whole partition and recreate a single partition to the full size.

Tom Howarth

VMware Communities User Moderator

[Santhosh_vmware]

Hi,

I have just simulated your scenario using openfiler and using iscsi software intiator,it did worked and no data is destroyed.Datastore finally contained two extents.On the same lun esx will treat two extents as two partitions,see attachment

here is the output

Device Boot Start End Blocks Id System

/dev/sdc1 1 900 921536 fb Unknown

/dev/sdc2 901 1904 1028096 fb Unknown

regards

santhosh

[Santhosh_vmware]

Hi,

I have simulated your scenario,using openfiler and iscsi intiator.It did worked no data is destroyed and finally vmfs volume had two extents.see attachments

Device Boot Start End Blocks Id System

/dev/sdc1 1 900 921536 fb Unknown

/dev/sdc2 901 1904 1028096 fb Unknown

Message was edited by: Santhosh_vmware

[Santhosh_vmware]

Tom is correct ,data on the existing lun will not be destroyed,but new lun will be formatted,

regards

santhosh

[Texiwill · Accepted solution]

Hello,

Since the second partition is an extent of the first there may not be problems with SCSI Reservation Locking, but if this was not the case, then you will definitely have problems. ESX VMFS is implemented such that a Reservation request will lock the entire LUN and not the individual partition. Due to this, use of partitions is really discouraged. You could get more reservation requests than you desire. I would instead either create a 2nd LUN and use that as an individual VM or create a new LUN of the proper size and copy everything over to it. With low end devices for iSCSI/SAN it is possible that SCSI Reservations will cause significant performance issues. To determine if you are suffering from this, scan the /var/log/vmkernel file for SCSI RESERVATION errors. If you are not then you may be safe.

Best regards,

Edward L. Haletky

VMware Communities User Moderator

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Author of the book 'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', Copyright 2008 Pearson Education. As well as the Virtualization Wiki at http://www.astroarch.com/wiki/index.php/Virtualization