topic Re: MSA2000 vdisk mapping in Disk Enclosures

MSA2000 vdisk mapping

ashliee — Tue, 18 Nov 2008 07:59:55 GMT

Hi, all.

Does anyone have any information about the following my situation?

I got an MSA2000, and tried to build a vdisk and map it to a windows OS.
I made 1073MB vdisk with MSA, and got 1GB new drive on the Windows OS.
After that, I configured a 536500byte vdisk on MSA to get new 500MB drive. Yet, the OS showed just only 499.65 MB.

Why such a kind of the capacity difference between MSA and Windows does occur?
How can I get a JUST 500MB disk drive on the OS?

Also, i'd like to know how many bytes are needed to configure other vdisk size, such as 2GB, 3GB, 4GB, 5GB,, etc.

Thanks.
Ashliee

Re: MSA2000 vdisk mapping

Uwe Zessin — Wed, 19 Nov 2008 07:50:21 GMT

Hello Ashliee,

it looks like you are fighting with the "Hardware GigaBytes" vs. "Software GigaBytes" problem.

Some software takes the number of logical blocks of a volume, multiplies it by 512 Bytes/Block and then divides it by (1000*1000*1000) to get the number of "Hardware GigaBytes". This value is usually printed on the disk drive hardware.

Other program code divides by (1024*1024*1024) and gets the number of "Software GigaBytes". The value looks a bit less, but it is just a different number system and not the cause for a law suit ;-)

It looks like this is the case with the MSA vs. Windows:

536.5/1.024/1.024/1.024 = 499.65456

Maybe you will never get a 'nice round 500 MBytes' on Windows, because you would have to create a volume of 536.87091199999998 MBytes which the MSA might not allow.

Re: MSA2000 vdisk mapping

ashliee — Thu, 20 Nov 2008 03:43:02 GMT

Hi, Uwe.

Thanks to reply to my post.
I did never consider the differences at all.

But I'll try 536.87091199999998 MB on MSA.