Mirroring rootvg

[KOG]

Hi Folks,

I am in the progress of drafting up the specs for a new pSeries server (probably 6E3) as the plan is to try and reduce the cost of oracle licence (based on no of processors). Probs is we are running on a v tight budget and I am trying to come up with the best solutions. I would like to mirror the rootvg but with the size of the discs on 6E3 (minimum size is 36gb) is it possible to mirror rootvg ON the same size? The manager is only prepared to afford 6 36 gb discs (I need at least 4 for oracle and 1 for backup so that leaves only 1 for rootvg).

Any suggestions?

Regards

K

 

[unixfreak]

I'm not sure I understand what you mean by mirroring on the same size? That's pretty much what you would always do.

Do you want to mirror on the same disk? That can easily be done but in my opinion it will reduce the life time of the disk because of excessive head movement.

Cheers

 

[KOG]

Hi

Many thanks for the quick response, I am no expert when it comes to mirroring the vg or lv (still newbie to aix) so wanted to explore all options before I finalised the spec form.

So ideally I should have another disc to mirror the rootvg? What are the steps involved, can I do it with smitty? Does it require a lot of admin work to monitor the mirrored vg or lv?

Regards

K

 

[PSD]

KOG,

You really need two disks for rootvg, mirroring to the same physical volume is pointless as the point of mirroring is to ensure server availability in the event of a disk failure. Mirroring to the same disks achieves nothing but slowing everything down i.e. two writes to the same disk as apposed to one.

As a sys admin I would never put in a system without rootvg having two dedicated disks mirrored exactly.

Cheers


PSD
IBM Certified Specialist - AIX V4.3 Systems Support
IBM Certified Specialist - AIX V4 HACMP

 

[unixfreak]

'mirrorvg -s rootvg hdisk1' id all it takes.

Cheers

 

[KOG]

Many thks for all your responses, will take them into consideration.

Regards

K

 

[bi]

You also have to run bosboot and change your bootlist to include the mirror disk as a bootable disk.

(And if you are in a production environment, not only should rootvg be mirrored, all your Oracle filesystems should be, too!)