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i have a HP EVA 4000 SAN now, what do you suggest in performance view. should i cut two 500GB raid 5 disks in the EVA and the do a disk expand in vsphere or i wont see any perfromance improvements?

thanks for you great tips

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How many drives are in the SAN are available for vSphere? Just two? Also, give us the type (ssd,sata,sas) size and speed. – jftuga Feb 10 '11 at 20:53
There are 40 15k Fibre optic disks in the SAN in total – Elgreco08 Feb 10 '11 at 20:59
up vote 3 down vote accepted

When you extend a datastore the LUNs are merely concatenated rather than stripped so you get no performance improvement.

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Especially on an EVA4000 where the LUNs are all on the same spindles. Due to how the EVA carves out space, both LUNs are occupying the same physical drives so striping won't gain any improvement versus concatenation. – sysadmin1138 Feb 10 '11 at 23:18
Thanks for the great tip! – Elgreco08 Feb 11 '11 at 10:48

If you have 40 15k drives available and are concerned about performance, I would consider creating multiple 2 TB raid-10 volumes. The max lun size that esx can currently handle is 2 TB -512 bytes accoding to this.

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