I have a HP MSA2040 600G*5 disk for a Raid5.When I create a Volume (2299.9GB),and I add volume to ESXi 5 datastore,it config and show 2.09TB result.
Why does it so much difference?
****I Know ESXi 5 VMFS5 block size (1MB)****
Who can calculate the capacity size(2.09TB)and tell me?
Hi,
I think this is because that when you have created your RAID5 volume, you have combined your 6 disks into one big lump of storage.
5*600GB = 3000GB of "advertised" disk space.
If you take what you have after RAID5 with (n-1) you get 2400GB of "advertised" disk space. (In reality this is going to be closer to 2299.9GB).
Now, when you format the disk with VMFS-5 you are formatting 2299.9GB of raw space presented to the OS. This is the advertised amount of storage you have as a decimal value. The system will be showing the binary representation of this, after formatting and such.
So taking this explaination into account you can work out:
Your storage amount * 0.9094947 = Your final useable storage
2299.9 * 0.9094947 = 2091.74686053TB
= 2.09 TB
I hope that makes sense?
As already explained by RyanH84, the MSA - by default - shows the "marketing" disk space, i.e. the base-10 size (GB) rather that the real, technical base-2 size (GiB).
Please take a look at HP Support document - HP Support Center for detail, and how to switch to the base-2 representation.
André