Mirroring Boot disk on EMC Symm with SRDF

[Nilesh Mistry_1]

I am looking to the scenario where a boot disk mirror resides on an EMC Symm that is SRDFd to a DR site. In the event of DR invocation, the DR host needs to boot up off the R2 copy and re-mirror to it's internal disks. The real problem is that EMC do not appear to support sharing "/" and "swap" on the same spindle. We do not want to use more than one spindle for this exercise ..... stalemate!

I think that swap does not have to be mirrored on the Symm as it does not need to be propagated in the event of a site fail over. Therefore what I am really looking for is a supported procedure for mirroring from R2 copy to DR HP server's internal disks in the event of a fail over, also taking into account the need to create swap volumes as part of the recovery process.

Hence I am after:
1. the specific mirroring process (commands) and how/when in the boot process it can be invoked
2. whether EMC will support swap on the same spindle, given it will only be used during the recovery/reverse mirroring phase and NOT during normal operation

[Byron Myers]

I support a system that uses SRDF to mirror root vg to a DR site. Our system does have / and swap on the same spindle - To my knowledge, HP-UX will only boot off an EMC that has its root vg on a single EMC spindle. You need to set up you root vg mirror to the EMC disk as you would any other disk (mkboot, etc.). I have responded to one of your recent postings on the requirements for using EMC disk for boot (I haven't got any points yet). You will definately need to mirror your primary swap to EMC, as HP-UX won't boot without it. The other swap partitions can be left out. For the specific mirroring process at you're DR site, mirror as you would any other logical volume: example "lvextend -m 1 /dev/vg00/lvol2 /dev/dsk/c8t5d0". as for when, to boot HP-UX at your DR site, you will have to:
1. power on the machine
2. interrupt boot process
3. boot from the DR site EMC root vg disk - interact with ISL.
4. at ISL prompt: ISL> hpux -lq -is
This will boot ignoring the primary mirror(s) and into single user mode.
You can then edit the /etc/fstab, and remove the entrys for the swap not on the EMC spindle. Here you can also mirror your'e LV's,
Each time you boot, interrupt and boot with "hpux -lq". You can add the additional swap any time.

Question 2 - EMC does support swap on the same spindle. I do it, and have successfuly performed multiple DR tests at our SRDF DR site EMC.

Don't forget points for this response!

[Patrick Wallek]

I cannot answer your questions directly, but I do offer one thing to consider. With your swap area, you will need to do something to make sure you have a primary swap area on your DR machine. I doubt that HP-UX will function very well without any swap.