Maximum Disk Size?

[Paul Masse]

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.

[Todd McDaniel_1]

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

[Todd McDaniel_1]

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

[Todd McDaniel_1]

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.

[Ashwani Kashyap]

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

[Paul Masse]

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!

[Jeff Schussele]

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

[Paul Masse]

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.

[Jeff Schussele]

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

[Geoff Wild]

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

[Paul Masse]

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.

[Todd McDaniel_1]

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

[Todd McDaniel_1]

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.

[Todd McDaniel_1]

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.

[Geoff Wild]

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

[Paul Masse]

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.