PDC Boot Disk Configuration

[susee_sundar]

Hi all,

I want to clarify the following Query from you all..

-->I heard that in PDC there are primary and alternate Boot disk configuration.

-->If primary fails to boot then the system start booting automatically from alternate boot disk and bring the system up.

My Query is :-

-->If the primary disk fails the system starts booting from the alternate disk..well

-->But the alternate disk is having a different controller and different target id and it will be sensed with different H/W path.

IF so..

-->then how the / & /stand will get mounted as specified in /etc/fstab file .....which indicates to the different H/W path..

Expecting the brief Explanation from guys

[Albert_31]

Hello Sundar,

Check the /etc/fstab file entries, here we specify the volume manager and not the disk details against teh mount point
ex

/dev/vg00/lvol1 /stand
/dev/vg00/lvol3 /

and not as (my understanding of the question)

/dev/dsk/cxtydz /stand

The volume manager will have the details about how to access the data (actually you have to configure it as well).
vgdisplay -v will be help you find out which disks are part of which vg.

Hope its clear now.

regards

Albert

[Fabio Ettore]

Hi,

consider that the alternate path for vg00 means essantially having two (or more disks) mirrored in vg00. That also means you can boot from the primary or from the alternate (if the primary is not available). You normally see the hw path pf boot disks by

setboot

or you can set this info by setboot in this way:

setboot -p
setboot -a

man setboot
"setboot - display and modify boot variables in stable storage"

Another way to configure that (but that I don't use so often) is by BCH and its interactive menu.

But think that if all is ok you will see the same info (about LVM, /etc/fstab, etc.) whether on the primary and the alternate disks.

After this can you explain better what is your doubt about / and /stand filesystems?

Sorry, just to understand better your question....

Best regards,
Fabio

[susee_sundar]

Both Of you are right.,

/etc/fstab

Contains the VG Information such that there is no Probs in hardware path.

Let us take a Situation :-

This is the Booting Sequence Upto My Knowledge.

PDC---> Boot Disk-->

Disk MBR Contains ( ISL --> AUTO file ( Which specify the location of kernel )

Boot disk --> ISL---> hpux --> Loads kernel

hpux utility in ISL starts loading the kernel specified path by the ISL AUTO file..

1..Let tell me whether the boot sequence is right.?

If Soo

2..If the Disk that contains the ISL Fails then how the system boots via the alternate disk.?

3..Is it,the alt disk also contains any kind of ISL in its MBR.?

If soo

4.. Then when & How it is get created..?

I hope now my query is clear

[Torsten. · Accepted solution]

The "MBR" of a disk used for a PA-RISC machine is called LIF area. The area is created with the command "pvcreate -B ..." and populated with "mkboot -l /dev/rdsk...".
In case you want to be able to boot the system automatically even if one disk is failed, you should set your bootstring to "hpux -lq" and enable "autoboot" and "autosearch" in BCH (boot console handler). Of course you have to configure the correct alternate hw-path to the disk.

[Arunvijai_4]

Hi Susee,

This may help you, http://docs.hp.com/en/B2355-60127/pdc.1M.html

-Arun

[susee_sundar]

Hi Thanks for the information now i am clear about PDC alt booting configuration.