7.54 What is the maximum filesystem size on a 7xx, running HP-UX 9.X HP-UX 10.X?

On a 7xx series, the maximum filesystem size under an *UNPATCHED*
HP/UX 9.01 is 2Gb.  There is a patch available which will increase
the maximum filesystem size to 4Gb.  Under 9.03, 9.05, and 9.07
the maximum filesystem is already 4Gb.

Under HP/UX 10.X, the maximum filesystem size is also 4Gb.

The maximum size of any file (not filesystem) is either 2Gb, or the
size of the filesystem on which that files resides, whichever is smaller.
Ie: You can not store a 1Gb file on a 500Mb filesystem.

The maximum size of the *boot* system is 2Gb under both 9.x and 10.x
You can play with this, if you have a > 2Gb disk, by allocating swap
equal to the balance, or some other such feature.  But in general, it's
probably best (at least for now) to use a 2Gb boot disk, and use that
bigger disk for something else.

>From:    Tom Lane <tgl@netcom7>
>
>Well, I *didn't* get it to boot off the Micropolis disk.  The key fact in
>all of this is that the HP S700 boot roms will not boot off a disk bigger
>than 2GB.  (I surmise that they use signed rather than unsigned longs in
>evaluating disk addresses.)  HPUX 9.03 and later can build filesystems
>on disks up to 4GB, so the HPUX filesystem code is unsigned-clean.
>But the boot roms ain't.
>
>HP's /etc/mkboot doesn't warn you about this; if you invoke mkboot on a
>4GB disk it will happily plop a bootstrap loader at the end of the disk.
>The bootstrap is useless, though.  The upshot is that you can use a 4GB
>disk as addon file storage but not as your root disk; the root disk must
>have a working bootstrap so it must be <= 2GB.
>
>All this is in the comp.sys.hp.hpux FAQ.  What isn't in the FAQ is that
>/etc/swapon also examines the bootstrap address (so as to avoid
>overwriting the bootstrap with swap space) and rejects the disk if
>the bootstrap address is invalid *according to the bootrom definition*.
>
>So, although you should be able to use part of a 4GB disk as swap space
>(by making the filesystem be smaller than 4GB), it's critical that you
>*not* have run mkboot against the disk, or else swapon will fail.
>I ran mkboot on the theory that it couldn't hurt.  Wrong!
>
>It turns out that /etc/rmboot will zero out the bootstrap pointer, so
>if you've made this mistake you can undo it with rmboot without
>damaging your filesystem.  Then swapon is happy.
>

Further confusing the issue under HP/UX 9.x on 7xx systems is not being
able to access more than 4Gb on any physical device without some wierd
manipulation (via sdsadmin).  In general, a driver from MDL (See 4.2)
is currently your best option if you have > 4Gb disk drives.  Under 10.x
this limitation is not there as you have access to LVM.

(thanks to Paul Hirose <pthirose@ucdavis.edu>)
(          Tom Lane <tgl@netcom7>            )