Question Regarding DISK LUNS in ESX

[ACHCHGUY]

HI All,

I have a question regarding LUNS in ESX using EVA shared Storage.

A while Ago I saw a video blog on evas with ESX and the techy was saying about creating a lun per vm...instead of one big lun for many VM's

Now I have been using this in esx 3.5 u2 and esx 4 and esx 4.1i and has worked really well.

I then had a discussion with a co worker Who uses traditional type san (assigning physical disk to a san LUN etc.

Rather than like the eva assigning all the disk to a disk group.

We had a great discussion about merits etc.

But I would like some feedback about this from the hp Community.

The only downside I see is yes you have to manage more luns...but I dont think it adds much time based on how easy it is to create luns in an eva.

Are there techy reasons why this is not good.?

I think disk space is better utilised as I only allocate disk needed when we create a VM and only what is required.

Not big luns up front that may not get filled or completely used over time.

I am interested in thoughts and technical reasons both from a san and esx view point.

Cheers
Steve

[Víctor Cespón]

A few documents about best practices to optimize performance:

http://h20195.www2.hp.com/V2/GetPDF.aspx/4AA1-2185ENW.pdf

http://www.vmware.com/pdf/Perf_Best_Practices_vSphere4.0.pdf

http://www.vmware.com/files/pdf/scalable_storage_performance.pdf

[Joshua Small_2]

Hi,

One big lun gives you a lot of flexibility.

One LUN per VM gives you management overhead and no benefit in my opinion.

[ACHCHGUY]

Hi Joshua,

Certainly agree that Yes you have to create more luns...but this takes less than 10 Seconds.(this was argued by co worker).

I would agree on an emc San this is a burden.

My counter arguement is that the one big lun means space upfront....and you have to manage what vm's go on in so as work loads match, scsi reservation issues etc...so the management overhead is Higher in my oppion on those one big luns over the life of that lun as you do have to be careful what VM you put on them with other vm's (so sharing that lun does not cause issues).

You dont get issues with is in the one vm per lun.

Cheers
Steve