topic Re: Maximum Disk Size? in Operating System - HP-UX

Maximum Disk Size?

Paul Masse — Wed, 21 Apr 2004 09:23:45 GMT

Can someone tell me what the maximum disk size supported by HP-UX 11i V1.6 and V2 is? I'm trying to use a 2.5TB device, but both operating systems claim the disk is zero bytes.

Re: Maximum Disk Size?

Todd McDaniel_1 — Wed, 21 Apr 2004 09:36:58 GMT

I know lli can support 2TB filesystems and files of 2tb as well... so You should be able to read it.

http://docs.hp.com/hpux/onlinedocs/5971-2383/5971-2383.html

Re: Maximum Disk Size?

Todd McDaniel_1 — Wed, 21 Apr 2004 09:38:20 GMT

oops typo... you should NOT be able to read it a 2.5TB LUN, etc...

Re: Maximum Disk Size?

Todd McDaniel_1 — Wed, 21 Apr 2004 09:42:51 GMT

One more thing...

for your max extents of 65535... your PE size will have to be rather large to accomodate a 2TB disk/LUN. Might give you some problems there...

no points here plz.

Re: Maximum Disk Size?

Ashwani Kashyap — Wed, 21 Apr 2004 10:59:11 GMT

From the vgcreate man page :
-e : maximum number of physical extents tat can be allocated from any of the physical volumes to a volume group . Max = 65535 .

-s : sets the number of MB in each physical extent , in the range of 1-256 and must be equal to a power of two .

So the maximum size of the physical voluem could be : 65535*256MB = 16776960MB

Re: Maximum Disk Size?

Paul Masse — Wed, 21 Apr 2004 11:57:41 GMT

I know that LVM has the limitations that you mention, but what about the OS? One symptom I have is that diskinfo displays a size of 0 Kbytes for my 2.5Tbyte device!

Re: Maximum Disk Size?

Jeff Schussele — Wed, 21 Apr 2004 12:11:23 GMT

From the JFS (VxFS) Supported Sizes page:

http://docs.hp.com/hpux/onlinedocs/5971-2383/5971-2383.html

11.11 using a minimum of JFS 3.3 ver 3 the max filesystem/file size is 2TB. That's probably why yours is reporting 0 bytes. Back it off to 2 TB & you'll be OK.

HTH,
Jeff

Re: Maximum Disk Size?

Paul Masse — Wed, 21 Apr 2004 12:18:52 GMT

Thanks Jeff, this is good information. But I'm not looking for volume manager or file system limitations, I need to know what the operating system will support. Everything works up to 2TB, but when the device is larger I get into trouble.

Re: Maximum Disk Size?

Jeff Schussele — Wed, 21 Apr 2004 12:26:03 GMT

Hi Paul,

You cannot separate the two. LVM in this case IS the OS. And Veritas' VxVM when run on HP-UX also has the same limitation for that matter.
The OS is only going to deal with what it's vol mgrs will present to it. So possibly until the next release of LVM (I checked and JFS 3.3 v4 & JFS 3.5 are still 2TB) or the next OS 11.11 v3, 2TB is going to be your limit.
There's going to be no way around that.

Rgds,
Jeff

Re: Maximum Disk Size?

Geoff Wild — Wed, 21 Apr 2004 12:27:48 GMT

I think a LUN of 2 TB is max - there's a DOC somewhere - question is why would you want a LUN that size?

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=53754

Rgds...Geoff

Re: Maximum Disk Size?

Paul Masse — Wed, 21 Apr 2004 13:13:47 GMT

Thanks Geoff.

Do you have any idea where the 2TB limit is documented? I've looked everywhere I can think of and can't find a clear answer.

My device is RAID protected and I have an application directly accessing the device, so I don't need the overhead or limitations that volume managers and filesystems impose.

Re: Maximum Disk Size?

Todd McDaniel_1 — Wed, 21 Apr 2004 13:23:15 GMT

Paul the link we gave you is the documentation for your question.

Re: Maximum Disk Size?

Todd McDaniel_1 — Wed, 21 Apr 2004 13:29:11 GMT

Paul,

You said: My device is RAID protected and I have an application directly accessing the device, so I don't need the overhead or limitations that volume managers and filesystems impose.

The limitations you mention are OS restricted... If you use LVM or Veritas, there is a physical limitation of 2TB.

There is no workaround for the OS for >2TB.

BTW, what SPECIFIC type of device is this that where it is 2.5TB... Largest single disk I know of is 181GB.

Re: Maximum Disk Size?

Todd McDaniel_1 — Wed, 21 Apr 2004 13:31:15 GMT

Sorry.. no points here...

The limitation is b/c of the HPUX OS if you look at the link we gave... NOT related to LVM at all.

Re: Maximum Disk Size?

Geoff Wild — Wed, 21 Apr 2004 14:07:10 GMT

Found this doc:

Maximum LUN Configuration and Considerations for HP-UX:
http://docs.hp.com/hpux/onlinedocs/netcom/maxlun-whitepaper-v1.0.pdf

I know I've seen a support matrix or something - I wish search was better on ITRC forums - I know I replied to a question sometime last year that had a link to what I think you are looking for - unfortunatley, searching does not seem to work when I search for my name and disk/lun...

Rgds...Geoff

Re: Maximum Disk Size?

Paul Masse — Thu, 22 Apr 2004 08:40:45 GMT

Thanks to everyone that has replied.

It appears that HP-UX does not yet support the 16 byte commands required to address devices larger than 2TB.

BTW - The device I am using is a disk array.