topic Re: DISK Size Limit ? in Operating System - HP-UX

DISK Size Limit ?

MikeL_4 — Sat, 03 Nov 2007 08:56:28 GMT

We have installed some additional SCSI disk that are 147Gb drives. We are using Veritas VxVM and when I initialize them they only show at 137Gb.

Is there some limit I am hitting ?, is there a way to get the full use of these disk ?

We are running HP-UX 11.11

Re: DISK Size Limit ?

Hein van den Heuvel — Sat, 03 Nov 2007 09:52:00 GMT

The explanation is: Marketing!

HPUX = 137 GiB = 137*1024*1024*1024 = 1.471e11

Manufacturer = 147 GB = 1.47e11 bytes = 137 GiB

See: http://en.wikipedia.org/wiki/Gibibyte

Hein.

Re: DISK Size Limit ?

rajdev — Sat, 03 Nov 2007 10:06:02 GMT

Hi,

What is your disk model , the 147GB is formatted capacity or unformatted capacity.
also what is the FS that you are using HFS/VxFS etc, each will have its own overhead, it should not take 10GB for overhead but you have to take all of them into consideration. what does bdf and diskinfo show ?

Regards,
RD

Re: DISK Size Limit ?

MikeL_4 — Sat, 03 Nov 2007 12:05:33 GMT

We are using VxFS File Systems but it shouldn't take 10Gb.....

I would say I got the Marketing Shaft on these new disk, thought I was getting 147Gb per drive and it ends up being 137Gb....

=>diskinfo /dev/rdsk/c4t9d0
SCSI describe of /dev/rdsk/c4t9d0:
vendor: ModusLnk
product id: MXJ3147SC800600X
type: direct access
size: 143638992 Kbytes
bytes per sector: 512

Re: DISK Size Limit ?

Hein van den Heuvel — Sat, 03 Nov 2007 12:44:48 GMT

>> size: 143638992 Kbytes

Please note how those Kbytes are truly 1024, not 1,000
143638992*1024 = 1.471e11

Back at those 147 marketing giga bytes where giga = 1000*1000*1000

Grins,
Hein.

Re: DISK Size Limit ?

Andrew Rutter — Sat, 03 Nov 2007 14:04:16 GMT

hi,

Hein is correct.

it has actually always been the case, but just alot more apparent now we have access to larger disks.

when you bought a 20mb disk you didnt hardly notice at all, a 4.3gb disk you bought only really got you 4.1gb and now as you see 147gb drive gets you approx 137gb.

All this is well documeted on every disk manufacturer's web site.

Just something that should be pointed out by sales people really, and marketing. especially if there selling say 10 disks for a storage solution? you've just lost 100gb without realizing.

Andy