Best way to monitor ASM disk groups for freespace

I ran into a problem a few weeks back where the ASM archive destination filled up.
I wrote a sql script to test the freespace in the disk groups against some thresholds and create a logfile. sqlplus will either exit with "0" - good or "number" numbers of exceptions or alerts. The shell script that calls it will tail the log for the #of lines returned from sqlplus and use "logger" to write a message to /var/log/ messages so our monitoring package will pick them up.

Is anyone else monitoring ASM for freespace? If so, how are you doing it? I heard that OEM will do it, but we aren't using it.

This works for us, but there are a lot of clever people on this list that come up with great solutions.
I was going to have the sql script use dbms_system to write the error to the alert log of the ASM clients, but one is a standby database and isn't open so dbms_system isn't available.

The OS is RH Linux and the db is 10.2 EE.

Thanks,
Steve

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