datastore size lowest then show at the storage

[maiconlp]

Hello, I don't know why when I go add a new datastore the LUN what I created in the storage appear at the VMware lowest then in the storage.

for exemplo, I created a new LUN in the storage with 60GB of size. but when I go to add a datastore this LUN appear only 55,88 GB from 60GB. where are the rest ?? where are other 4.2 GB of my LUN. in the storage it appear with 60GB.

why VMware regard only 55,88GB of 60GB ??

attached follow an screen shows created datastore

thanks

[weinstein5]

Previous versions of VMware - about a 1 GB was carved out of the datastore to hold the VMFS datastore metadata - I am betting this is what is happening but I am surprised by the amount of space being taken - 

[TomHowarth]

my guess is that it is metadata,  each peice of data, will need a checking a verifying and its address stored in the metadate,  what version of ESX are you running and what version of VMFS?

[a_p_]

The storage systems seem to use the "Marketing" GB sizes (base 10) whereas ESXi uses the real sizes (base 2).

On the storage 60 GB equals 60 * (1000 * 1000 * 1000) = 60, 000,000,000 Bytes. If you take the byte size and divide it by (1024 * 1024 * 1024) you will end up with 55.88GB.

André

[maiconlp]

Hi, ESXi 4.1 I don't know how I can see the VMFS version....

[maiconlp]

Hi, thanks.

So.... I Can't change this issue right ?

is very hard loss theses amount of the disk space!

thanks

[a_p_]

Basically the storage system "lies" on you and shows more capacity than it really has due to this marketing calculation Usually there is an option in the storage system's configuration to show the real size rather than the marketing size. This will at least allow you to create the LUNs with the desired size.

André

[maiconlp]

So.....Thanks!

My vendor storage is HP model MSA 2312i. I will contact HP.

[a_p_ · Accepted solution]

Just found HP's Support Document HP StorageWorks P2000 MSA - Volume size Difference Between the OS and the MSA.

André

[maiconlp]

Thanks! very good