Hi!

Thank you for the answer. I have been reading the "PowerVault MD3000 and MD3000i Array Tuning Best Practices" and in matter of Performance seems that the answer is: Isolated Disk Groups with a minimum number of Virtual Disk (Only one ideally). That was my first option but now I have to decide if we can sacrifice some performance in order to have more space. The eternal doubt :)

I will try to benchmark the two options if I have enough time.

cheers,

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From: i.dell.com/.../PowerVault_MD3000_and_MD3000i_Array_Tuning_Best_Practices.pdf

(page 9 - Virtual Disk Location and Capacity)

"Virtual disks are aligned in series within a Disk Group with the first virtual

disk starting in the fastest outer regions and progressing inwards. When taking

this into account, a disk group should be designed with as few virtual disks as

possible.  

Dell™ does not recommend using more than four virtual disks or repositories per

disk group for peak performance. Additionally, where performance is critical,

isolate virtual disks to separate disk groups as possible.  

When multiple high-traffic virtual disks share a disk group, even with purely sequential usage models,

the disk group I/O behavior becomes increasingly random, lowering overall

performance. Additionally, when a disk group must be shared, the most heavily

trafficked virtual disk always should be located at the beginning of a disk group."