topic Re: splitting boot disk in two in Operating System - HP-UX

splitting boot disk in two

Bill McNAMARA_1 — Tue, 15 Oct 2002 06:32:04 GMT

Hi,
I've got a few servers in a training environment that regularly are subject to harsh treatment.. too often a rescue needs to be performed that takes waaay too long - ignite etc. I'm toying with the following ideas, but there is one that is kind of interesting.. meerly for a technical interest!

o split mirrors
- requires two disks
+ no messing around to boot from second

o dd
- 2 disks
+ quick and dirty

o ignite
- multiple server models,
- images are massive and need updating
- takes too long to restore

o split boot disk in two partitions..
-> okay so this is where I need help:
I can install hp-ux on vg00 of a 9G disk in 4.5 GB.
on the other 4.5 I could create an identical file system structure as the first half, modify a few files (fstab etc..) and have a backup on the same disk.
Assuming that lvlnboot can still be used when the system is cacked up (which it is 99% of the time) will we end up with the following problem?:
- booting?????????
ISL> hpux boot=/dev/vg00/lvol10?

or does the disk label via lvlnboot take care of all that..?

Later,
Bill

Re: splitting boot disk in two

John Palmer — Tue, 15 Oct 2002 06:59:42 GMT

Hi Bill,

Nice idea. Unfortunately, the boot LV must be the first LV on the disk (see man lvlnboot).

You could possibly create a copy of each vg00 LV in the spare 4.5Gb (maybe even create vg00 as a single LV) and copy them back when needed but you'd have to do this from an alternative boot - recovery CD? What servers are they? If they've got hot plug disks then you could keep a spare bootable disk that you could plug in and boot from when necessary.

Regards,
John

Re: splitting boot disk in two

Jean-Louis Phelix — Tue, 15 Oct 2002 07:06:57 GMT

Hello Bill,

I'm afraid that hpux at the ISL prompt will use information from BDRA to access directly to root, boot and swap. But there is only 1 BDRA per disk ... Perhaps you could try to boot on Support CD, activate the vg00 and use lvlnboot to change BDRA. But my feeling is that if your lvol10 is located in the same vg00 as the other ones, it won't be a safe place to protect your backup from students ...

Regards,

Jean-Louis.

Re: splitting boot disk in two

Leif Halvarsson_2 — Tue, 15 Oct 2002 07:12:25 GMT

Hi
Do you use a Ignite tape or Ignite server ? I don't know was "too long" is but my experience with Ignite server is, if restoring a resonable fast computer/disk and use a 100MBit lan, Ignite is very fast. Perhaps 10 minutes to restore a A400 with a >1GB image (including the two reboots).

Re: splitting boot disk in two

Dietmar Konermann — Tue, 15 Oct 2002 07:51:04 GMT

Bill,

I tend to agree with Leif proposing an Ignite-based approach... the only student-proof approach needs to be ccompletely independent from any built-in disks and their ability to bootup the machine. :)

If you really want to use no tape, no Ignite server, no CDROM and only a single disk, then a combination of dd and the 2-partition approach could be an idea (of course also quick+dirty).

Install HP-UX with vg00 consuming the 1st half of your disk. When the system is prepared you boot to single-user and perform a dd of vg00 to the space behind it.

In case of need boot to single user, dd the image back and perform reboot -n. Of course a little bit ugly, but should work. You are trouble when system is unbootable or someone writes behind vg00. :)

Regards...
Dietmar.

PS.: Use Ignite.