Mirroring Root Disk to EMC Symmetrix

[Nilesh Mistry_1]

Are there any white papers relating to the above topic, or has anyone tried it? Is it possible to boot directly off a symm? How do you handle swapfiles etc?

Any information / white papers would be useful.

Thanks for your help.

Nilesh

[James R. Ferguson]

Hi Nilesh:

I think you will find thread's discussion very interesting:

http://forums.itrc.hp.com/cm/QuestionAnswer/1,1150,0xddfba14d9abcd4118fef0090279cd0f9,00.html

...JRF...

[Darrel Louis]

Nilesh,

If you do a search within the forums for EMC boot you will find some interesting threads.

It's not advisable to boot from a EMC disk.

Regards

Darrel

[Jason VanDerMark]

Some useful information regarding the EMC Symmetrix and HP servers can be found at the following URL:

http://www.google.com/search?q=cache:www.docs.hp.com/hpux/pdf/B5736-90025.pdf+mirror+root+to+emc+symmetrix+&hl=en

This is the pdf contents converted to text. The following URL is to the pdf file itself.

http://www.docs.hp.com/hpux/pdf/B5736-90025.pdf

Hope this helps.

Good Luck,
Jason V.

[Steven Sim Kok Leong]

Hi,

If both the primary and its copy are in the EMC, then it would post a problem. If the fibre or box is down, everything goes.

However, if the primary root VG resides in local disks and the root VG mirrored copy of LVs resides in the EMC, perhaps it will not pose an issue since it is unlikely that both the local disk and EMC will fail at the same time.

Just my 2 cents. Regards.

Steven Sim Kok Leong
Brainbench MVP for Unix Admin
http://www.brainbench.com

[Byron Myers]

Yes, we do it in our shop. For HP-UX to be able to boot from a Symmetrix, the physical EMC disk that the root hypervolume resides must not have any other hypervolumes on it. For example, if you want a 4 GB root volume, the EMC disk is 23 GB, then one and only one 4 GB hypervolume will exist on this EMC disk - the remaining 19 GB will be unallocated (wasted). In addition to this, One I/O port on the Symmetirx will be dedicated to this one LUN (hypervolume). That is, one controller in you HP system will see only one LUN - the single LUN from the one physical disk on the Symmetrix system. We mirror from our internal root disk to a Symmetrix LUN configured as above - it works like a champ, and best of all its supported.

[Nilesh Mistry_1]

Thanks for your help ... here is the situation in which we are thinking of using it ...

I am looking to the scenario where a boot disk mirror resides on a 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