mirrorvg

[rondebbs]

Hello, I am ruuning aix 5.2 ml3 on several p670 boxes. These servers are connected to our EMC dmx1000 for storage. I am using mirrorvg to migrate from standard symmetrix volumes to striped meta volumes.

The process is pretty straight forward -
1. Extendvg AIX Volume group with new striped meta volumes
2. Mirrorvg old std volumes to new striped volumes
3. Unmirrorvg old std volumes
4. Reducevg old std volumes

Once this is done the VG has now been migrated to the new striped meta volumes and it performs much better.

I have migrated many volume groups during the day while users, applications and databases are running. I am now ready to migrate some VGs that contain our larger progress databases. The DBA's are asking for an outage where we can bring the progress database down before migrating it. They are concerned that the database may some how become corrupt during the migration even though I have migrated other progress dbs without any issues. It can be difficult to get down time in our 24x7 environment.

Does anyone see a problem with using mirrorvg to migrate database VGs when they are online and in use. As I said before I have never had any problems with mirrorvg in the past even when it is run at a time of heavy acctivity on the VGs and file systems.

 

[p5wizard]

I would not expect any problem with corruption, however I would suggest doing your syncvg-ing in the nighttime or whatever other low-load time you have.

The syncvg is run by mirrorvg automatically, but you can ask mirrorvg to not do the syncvg, and schedule the syncvg in the off-hours. See man page for mirrorvg (I think it is -s flag).
Just don't do the unmirrorvg as long as the system is still doing the syncvg for you...

All syncing between the copies is done through the system's IO buffers, so that work does interfere with your normal IO load. (interfere as in: your users will notice the extra load on the machine).


HTH,

p5wizard