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humanxbox
Contributor
Contributor

Disk / LUN / VMFS size recomendations for VM ?

Hi

I am looking for a manual with best practices for setting up LUNs and sizing and vmfs before installing ESX server 3.0.2. Would like to know what are the recomendations, 1 vmfs = 1 lun ?? General practices ??

please help

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b_o_f_h
Enthusiast
Enthusiast

Hi,

The maximum possible for VMFS is 2 TB, but the recommendation is ~ 500 GB max..

I have 4 LUN's with each ~ 700 GB and all with 1 VMFS (using the full LUN always). If i remember correctly, there is also the recommendation not to put more then 10 VM's on a LUN (but this depends on the SAN behind and the Disk I/O it can provide).

chandlm
Expert
Expert

Unfortunately the answer is the same as for most questions looking for specific configurations..."It depends". I know there are quite a few discussions on the forum about this, did you try searching already? I use LUNs sized about 500GB depending on how the SAN layout works.

http://communities.vmware.com/thread/36725

http://www.vmware-land.com/Vmware_Links.html#Storage

mcowger
Immortal
Immortal

We do 534GB LUNs (created as a LUSE of 16 * 33.4, our standard LUN size).

--Matt

--Matt VCDX #52 blog.cowger.us
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James-D
Contributor
Contributor

There is also the thought of using a Lun for each VM. The benefits of this are that it can increase throughput for iSCSI as each VM will have its own I/O queue. Also it can mean that snapshots and clones can be done of individual machines using your SAN which is likely to be quicker than using virtual center. ESX can support up to 256 Luns per datacentre so for small to medium enviroments this is a good solution. Smiley Happy

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chandlm
Expert
Expert

I would think you would need to have an EXTREMELY understanding SAN team for that to go over well.... Smiley Happy

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azn2kew
Champion
Champion

We're having corporate wide settings and standardizations on:

LUN size: Between 400 - 600GB we recommend 500GB is decent.

VMs per LUN: We don't want to use anything more than 15 VMs because it tends to come down with performance issue if you stack too much VMs in a LUNs.

VMFS 3 is currently standards for newest VI 3.5 so you're good shape. Make sure you have good redundant infrastructure with SAN and Networking in place.

Good Luck,

Azn2kew

If you found this information useful, please consider awarding points for "Correct" or "Helpful". Thanks!!! Regards, Stefan Nguyen VMware vExpert 2009 iGeek Systems Inc. VMware vExpert, VCP 3 & 4, VSP, VTSP, CCA, CCEA, CCNA, MCSA, EMCSE, EMCISA
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James-D
Contributor
Contributor

I guess thats where im lucky enough to wear the hat of both the SAN team and ESX team Smiley Wink

James

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snantel
Enthusiast
Enthusiast

I agree with the 500gigs size. But again, all depend what you will run on it.

For me, I only running OS into vmfs and others non critical servers having data no more than 150g.

All my critical servers (exchange, file server, sql) the data is running on a RAW LUN.

You also keep in mind that for now, there is a limit of 250 LUNS by ESX cluster.

And keep an eye on your LUNs SAN performance. If your VM create too much IO, you will have to increase the disk spindles on your LUN or to move your VM on a separate LUN.

Also keep in mind that if you put large data into a vmfs anstead of a RAW LUN... you may be run into a problem if by example you call Microsoft for a problem and they ask you to bring your server into a physical box. With a RAW LUN, it is a peace of cake. With a vmfs, you will have to migrate the data into a LUN and this is not fun.

Moving a server from ESX to Physical or Physical to ESX is very easy when you keep your data on a separate LUN.

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