Pros and cons of having one LUN per volume?

[NOWNOWNOW]

When setting up LUNs for use with Vmware, what are the pros and cons of having each LUN in its own volume, please?

Thanks!

Richard.

[ken_foster]

snapshots happen at the volume level so if you have multiple LUNs in a volume they all get snapped at the same time, whether they are all consistent or not.

Pro's of one lun/volume

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1:  only have to quiesce the one lun when you want to take a snapshot

2:  can use snaprestore to restore the volume quickly. (potential performance hit with single file snaprestore)

Cons of one lun/volume

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1:  more complicated setup

2:  volume count limitation

thats all i can think of for now.

[shaunjurr]

Hi,

Additional Pros:

1. Since you can prioritize I/O on a per volume basis with FlexShare (a.k.a. priority command) it is perhaps an advantage not to mix more than one LUN per volume unless they are the same "class" of I/O.

2. Related to other snapshot operations:  snapmirror operations to secondary storage can be differentiated a bit more on a per-lun basis. Moving luns to different aggregates can be one on a per-lun basis

Often enough, these things are just a matter of flexibility versus complexity.  As long as you aren't going to need hundreds of volumes (depending on the unit you have), one lun per volume is probably not a bad thing.  Read up on the Best Practices for setting up storage for vmware.  It can be a lot different than you think if you have used other storage systems.  Strategies like joining/concatting lots of small luns is pretty pointless on a NetApp.

Good luck.

[DONALD_R_GRAY]

De-duplication happens at the volume level, so if you have multiple luns with similar data like vm's you will save more space having them on one volume.