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1987
October 10th, 2012 11:00
'Extend' Datastore Capability Using EMC VSI Plugin
A question about what actually happens when using the "Extend" capability was recently brought up in some discussions I've had and thought it would be a great idea to post it here for everyone's reference. Below is the question:
Q: In going through a VSI-Flex demo (shown at VMworld 2012 SF) I noticed the actions dropdown menu had an “EXTEND” option for VMFS. Does anyone know how this is done? Can you extend the LUN under the covers and not break VMFS, or is this concatenating a new LUN (extent) to the existing VMFS DataStore?
A1: It depends..You can extend a Vmfs volume within the same lun. Aka "volume grow" Or add another lun to the 1st lun (up to 32 extents). You will find "stitching" two or more extents as a bad practice due to the fact that the Metadata is stored on the 1st datastore
A2: Lun grows within the storage pool it lives on ……..all happens on the backend, that is the magic of using storage pools on VNX J Sad part is there is no ‘shrink’…..
A3: When you grow the LUN on the backend the VMFS automatically detects the increase and expands into it. It just adjusts the GPT for the new size. Its not automatic (you have to tell it to do so), but with the VSI that process is automated, so it looks like magic
Zack.Zhang
44 Posts
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October 22nd, 2012 00:00
This information is helpful!
So by extending a VMFS datastore using VSI, no new extents are added (Which is different from the method I always use to expand my VMFS datastore using the vSphere native "add extent" functionality)?
cgermain_05286b
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October 22nd, 2012 00:00
Hello,
I will be out office on business Monday October 22, ,2012 - Friday October 26, 2012.
Should you need immediate assistance please contact the Help desk at 1-877-362-4843 or at extention 5370.
Thank You
Chris Germain
Delaware North Companies Inc
Infrastructure Services
Sr. Systems Engineer
Phone:(716)858-5391
Cell:(716)573-5391
Email:cgermain@dncinc.com
Thank You
Chris Germain
>>> "Zack.Z" 10/22/12 03:02 >>>
Zack.Z created the discussion
"Re: 'Extend' Datastore Capability Using EMC VSI Plugin"
To view the discussion, visit: https://community.emc.com/message/683616#683616
marquesj
28 Posts
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October 22nd, 2012 06:00
Yup thats right. We try to shy away from leveraging VMware extents due to its added complexity. Why not be able to take advantage of storage array functionality by simply growing the existing volume underneath and letting vsphere see the extra space? Thats exactly what gets done when you leverage the extend feature on the vsi plugin when growing a VNX storage pool LUN.
Glad this was helpful Zack. Thanks for posting.
Jason
Zack.Zhang
44 Posts
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October 22nd, 2012 18:00
Thanks, Jason, glad to see there's such a way to extend the existing volume