Is it possible to mirror between different logical volumes?

[TSch]

Hi folks,

following situation:

Two RS6000 in LAN.
First Machine got an lv, lets call it "A".
This lv is nfs exported and mounted on second machine.
Second machine got an lv, lets call it "B".

Is it possible to mirror lv "B" to lv "A"?

If yes, how can it be done?

Thanks in advance !

Regards
Thomas

 

[AIX5L]

Hi

You have mounted a Filesystem and not the Logical Volume.
A mirror will only work with the Logical Volume.
To mirror a LV/JFS the Lvs must be in the same Volumgroup.
A JFS must have the Same Loglv.
Wy you want to have a mirror on B ?

You can work with shared Disks, that can be accessed by both machines ( but not varyon the Volumgroup on both machines )

 

[TSch]

Problem is:

the first machine's got an oracle database residing on ESS disks connected via scsi.

Now we'd like to mirror these contents constantly onto some ssa disks residing on another machine in our network (in case ess breaks down), which is meant to act as the backup machine.

 

[AIX5L]

If you have one SCSI Adapter in ESS free you can access the same ESS Disk with your Backupserver.
I think ESS is a full tolerant System ;->
you can Share the SSA Loop on both Systems and access the Disks from both Systems. ( on Machine A varyoffvg, on Machine B varyonvg )

Does the backupmachine works in a other Environment ?
Wy you dont use HACMP ?

 

[Chapter11]

You might be better off looking into Oracle's functionality for replicating databases in this case. An OS-type solution across the hardware you have looks rather difficult.

 

[Yegolev]

Or you should use the ESS for the functionality. It should have the capability to maintain internal mirrors for redundancy, plus you can cable both hosts to it and share the frame. We use mostly EMC frames but have one IBM storage frame (for TSM), but I suppose IBM has imitated EMC for the most part.

For your situation you should go with HACMP instead of a home-grown solution, in my meager opinion. It can handle the disks from the AIX side, and with proper ESS config you should not have to worry about mirroring or anything on the AIX box. If it works like EMC. IBM Certified -- AIX 4.3 Obfuscation

 

[TSch]

Problem is that we had extrem downtimes while using HACMP caused by HACMP. Therefore we removed the software from our system...

 

[Yegolev]

You should be careful what ports you scan when using HACMP. =) We keep it on a separate network, otherwise we would have lots of trouble.

Maybe you can still do the mirroring inside the ESS and share disks? ESS should be faster than any other method of mirror. EMC can even mirror between frames, not sure about ESS. IBM Certified -- AIX 4.3 Obfuscation