LVM and VxVM

Re: Question on PE, boot sequence and hardisk

 
Ngoh Chean Siung
Super Advisor

Question on PE, boot sequence and hardisk

Hi,

1) According Chp 16 - LVM (Software recovery Handbook), the LVM header have to be fixed into a PE.
a) Is it possible to know the actual location of this PE? Is it the first PE?

b) How to check the remaining size or extra info about this PE?

c) What is the impact if the size for this PE is full?

2) How to determine the boot sequence for a server? Using ioscan -fn? Can I change the boot sequence? How?

3) How to determine the harddisk is non-bootable or bootable? According Chp 16 - LVM (Software recovery Handbook), the LVM header of a bootable disk is always 2912 KB. Is it still the same even having larger PE such 8MB, 16MB and etc?

regards
4 REPLIES 4
Steven E. Protter
Exalted Contributor

Re: Question on PE, boot sequence and hardisk

Item 2 and 3

lvlnboot -v


Shows you this information.

The LVM chapter of Keenan's book HP CSE will give you a bit more information on this sujbect.


Some docs to help.

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B3921-90010/B3921-90010_top.html&con=/hpux/onlinedocs/B3921-90010/00/06/632-con.html&toc=/hpux/onlinedocs/B3921-90010/00/06/632-toc.html&searchterms=boot%7cdisk%7clayout%7clvm&queryid=20041129-201804

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Sridhar Bhaskarla
Honored Contributor

Re: Question on PE, boot sequence and hardisk

1.

a)Yes. It's the first PE.
b)There is not any 'handy' command to get that information. You can use 'xd' or 'adb' to query some information that you normally do not require to do.
c) Enough size will be allocated to hold the information when you create the VG. This is one of the primary reasons why you cannot modify VG configuration parameters once it is created. If it is not sufficient, it won't let you create the VG until you change the parameters to fit to that extent.

2)If you are talking about "path" information, use 'setboot' command. It will display the primary and alternate paths. For cell-based systems, it's slightly different. Use "parstatus -V" for cellbased systems.

3)Check the LIF and auto files.

lifls /dev/dsk/cxtydz
lifcp /dev/dsk/cxtydz:AUTO -
Or use lvlnboot -v command. The disk should appear as "boot disk" in there.

Yes. 2912 KB is fixed irrespective of PE size.

-Sri

You may be disappointed if you fail, but you are doomed if you don't try
Ngoh Chean Siung
Super Advisor

Re: Question on PE, boot sequence and hardisk

Hi,

1) Assumed that I already create a vg called vg00 with PE size is 8MB. My concern is the LVM header for bootable disk is 2912KB and for non-bootable disk is 8MB. Am I right? This particular PE size will increase from time to time if I added more LV and PV to this VG. What happens if this particular PE size that used to store the LVM header is full? Means I cannot do all the LVM activities such as add new LV, PV or etc, right?

2) For the boot sequence, how to check what is the first thing that server will run? Same as normal PC, we can go to the CMOS and have a look at the boot sequence (Flopply disk -> hard disk -> cdrom). How about in HP-UX server?

regards.
Senthil Kumar V
Occasional Advisor

Re: Question on PE, boot sequence and hardisk

Hi,

LVM Header size of boot disk is always 2912 KB. In case of non-boot disk it is much small in size, because it will not hold any ISL utilities and BDRA.

LVM Header will not hold details in each PE, but it will hold essential details like PV-ID, VG-ID, No of PEs and Size of PE.

So the LVM header is unlikely to grow when your VG grows to any size.

ISL>display should show you the primary, alternate and console Hardware path.

You can view the devices using sea command at PDC.

regards,

Senthil