root disk partitioning for mirroring

[yash123]

thanks a lot Torsten for sharing the knoweldge...

I believe it is better to mirror partition 1 and 3. What's your opnion?
How to mirror part 1 & 3? is it possible through lvm mirror.

[Viktor Balogh]

> How to mirror part 1 & 3? is it possible through lvm mirror.

No, these are not under LVM control. To mirror these partitions, you can use dd like this:

# dd if=/dev/dsk/c0t0d0s1 of=/dev/dsk/c1t0d0s1
# dd if=/dev/dsk/c0t0d0s3 of=/dev/dsk/c1t0d0s3

This will create a verbatim copy of these partitions to your second disk.

[P Arumugavel]

Hi,

No need to copy the EFI partion to mirror disk. You copy only the contents of the HPSP partition; that also if the diagnostics have been installed to the original system disk. To see if the diagnostics are installed on the original boot disk; use

# /usr/sbin/efi_ls -d /dev/rdsk/c0t0d0s3

If present, copy them with the Viktor Balogh's command.

Note: dd command may fail to copy the HPSP partition if the sizes of both primary HPSP and alternate HPSP partitions are not the same. If dd command fails with I/O error, then the alternate way is to copy them to HPSP partition from Offline Diagnostics and Utilities CD-ROM.

Rgds...

[P Arumugavel]

Use the following commands to find the size of EFI, HPUX & HPSP partions on original disk.

EFI:
#/usr/sbin/diskinfo -b /dev/rdsk/c0t0d0s1 | awk '{print $1 / (1024)}'

HPUX:
#usr/sbin/diskinfo -b /dev/rdsk/c0t0d0s2 | awk '{print $1 / (1024)}'

HPSP:
#usr/sbin/diskinfo -b /dev/rdsk/c0t0d0s3 | awk '{print $1 / (1024)}'

Each will give you the value in MB

Rgds...

[Torsten.]

Only a hardware mirror can mirror partition 1 and 3 - LVM cannot.


But there is not really a need to do this.

If the mirroring procedure is correctly done, both disks are bootable.

Just make sure the second disk is listed in

/stand/bootconf

because if a patch is updating the OS loader it will update both disks then.



Don't worry about partition 3 - if you ever need a **current** tool, you need the current CD anyway.