Imbalanced CPG

[tiger_woods]

Hello Gurus,

We recently bought additional 600GB FC disks to increase our spindle count on this CPG and add more capacity. I have done the following steps to re-balance the VV distribution across all PDs:

1. Created a temp CPG with just the new disks
2. Moved each VV to this temp CPG
3. Moved each VV back to the original CPG

Note that no modifications were made on the original CPG as the CPG setting was already set to use all 600GB FC disks (-devid XXXXX). With this setting, 3PAR should just use the new disks straight away.

After doing this, I noticed that majority of the chunklets were still on the original 32 disks and only a small few were on the new disks. I ran a tunesys on the CPG and I didn't get much space back either.

Anyone's seen a similar issue? The system's on 3.1.1(MU2). Can't upgrade yet due to political reasons.

Thanks in advanced.

Rom

[hdtvguy]

I don't think you needed to create new CPGs, I think you just needed to do a tunesys? What parameters did you use for the tunesys?

[sunieal]

Just run tunesys -dr (dry run) which will let you know whether you need any tuning in terms of LD's or inter-node balancing. If it says no tuning required your system is balanced enough.

[rotorhead1]

Yes this is by design and must be done each time you add disks according to HP. Since the VVs are created in the original CPG, the chunklets do not move until you do a tunevv. We added about 100TB of FC and 200TB of NL recently and had to create a new CPGs and migrate the VVs. We did try to tune directly to the same CPG and it does work. But we elected to migrate to the new CPGs to keep it clean. FC easy and quick, NL took forever obviously.