HowTo: Reorg physical disks under ASM

Let's say I have one or more disks/mounts in an ASM disk group and I want to get all of my data off of this disk and then remove it from the disk group. How is this done?

Answer:

When I first built my lone ASM instance (+ASM), I had SysAdmin create 2 300GB RAW mounts and made them into a single disk group to be used by a single instance.

This setup lead to very poor ASM throughput of about 2MB/sec (and this is off of an 200MB/sec EMC SAN!). This is on a 64-bit AIX 5L box with each mount only having only a single LUN (which they did not bother to disclose to me until AFTER i reported slowness!).

So what i decided to do was to start again.

I went back to the SA's and ordered 20, 25GB mounts with a unique LUN for each mountpoint. After the space became available I added it to my existing disk group (DGROUP1) and let ASM rebalance itself over night.

Now, here's the genius part: All you have to do to get your data off of a disk and remove is to just go into the OEM Grid Control ASM Disk Group page, select the disk and click the "Remove" button.

ASM AUTOMATICALLY rebalances the data off of this one disk onto the remaining disks and then drops the disk!. How great is that?

Once you've selected a disk and clicked "Remove", you will see that the disk now has a status of "Dropping" (see screen-cap below).



You can also monitor the progress of the drop operation by using the "Pending Operations" link under the General section heading on the Disk Group page (see screen cap below).