Root disk mirroring in itanium HPUX

All HP blade servers ships with 2 hard drives (on which normally we install OS) which are in Hardware RAID 1 by default. Which means they are in mirror serving high redundancy to server. If one disk fails, server continues to work from second disk. But in case of vPars, iVM and blades where hardware raid is broke manually, we need to do software mirror for OS disks. This is called as root mirroring i.e. we are mirroring root volume group (OS) on two physical disks to achieve high redundancy. Lets see step by step root disk mirroring for HPUX running on itanium platform.

Step 1.

Create a partition file which will be used to write on disk to define partitions on physical disk.

Here we are defining 3 partitions (1st line). EFI partition with 400MB size which will house EFI shell. HPSP i.e. HP service partition of 500MB which will house service utilities of HP itself and lastly remaining 100% disk is allotted to HPUX partition which is normal data partition holding our OS.


Step 2.

Identify disk on server which is to be mirrored with current root disk. This can be done using ioscan -fnCdisk & insf -e -C disk command. Once identified (lets say disk2 for example) we will write above partition file on to disk using idisk command.


Step 3.

Make the disk bootable with mkboot and write boot instructions on it. Here we are using -lq argument with boot string to make sure server boots without quoram when one of the disk fails.

Verify if boot string is properly written on first partition i.e. EFI partition of disk


Step 4.

Now we are taking this disk into OS LVM and mirror. Create PV on this disk. Make sure you use -B argument to understand LVM that its bootable PV.


Step 5.

Extend current root VG vg00 to accommodate this new disk.


Step 6.

Mirror all logical volumes on current boot disk on new disk using mirror copies (-m) as 1 in argument in lvextend command.

This task can be easied with for loop. Observe number of lvols in your current VG and run a for loop like one below.


Step 7.

Second last step is to set boot, swap, dump and root volumes on new disk.

Verify it


Step 8.

Add new diskname in /stand/bootconf file. Here l means disk is managed by lvm.

Lastly set new disk’s hardware path as a alternative boot path and you are done. Hardware path of new disk can be obtained from ioscan output.

Verify it

Your root mirror on new disk completed!!

You can reboot system and try to boot from alternate disk from EFI to test.

 

Any thoughts?