PPSize migration question

[lremoort]

Hi,

I face following situation :

My customer is running AIX (4.3 and 5.2) in HACMP cluster.
At the moment they are running on Shark.
They use host-base mirroring (LVM). They have a PPSize 8MB, they have already a maximum of 32 LUNs in a VG.

What my customer wants is to migrate to a EMC Symmetrix.
In the mean time they want to make the PPsize bigger, so they can create bigger LUNs. They want a new PPSize of 64MB.

They also want this migration to be performed on-line, or with the least downtime possible.

How should this be done, I have no clue. Are there specials tools for this ? Special commands or strategies ?

Thank you very much for your help.

Regards,
Luc

 

[theycallmetim]

You don't have to have a bigger PP size to create bigger LUNs. You can to a chvg -t {factor} to increase the max number of PP per pv. You can use the -B flag to allow more pv per vg as well. That being said. If you wanted increase them anyway, you would have to create a new vg on the Symm with the bigger size and copy the lv over (cplv).

1 more question. Are they running AIX 4.3 and 5.2 in the SAME HA cluster? You can only do this if they are running 4.3.3 or higher.

 

[lremoort]

Hi,

They are using 4.3.3 and 5.2. But not in the same HA cluster.

chvg -t and the -B flag, does this mean that they will migrate to BIG Volume groups ? I have heard that AIX Big Volume groups have a lot of performance problems.

Regards,
Luc

 

[theycallmetim]

Yes, -B does mean big vgs. I have not heard any performance degradation in this mode. (Not to say that there won't be)