symcfg discover

As RRR said first thing I do is a symcfg discover or I restrict it with a -sid xxxx and you can also do a symcfg -sid xxxx verify to bounce the database against the machine to check that its up to date.

i found its not risky but lengthy

If your Symm has 10k symdevs it can be lengthy yes.... But nondisruptive

lengthy is a good word for it. I have a hard time getting the guys to run it before doing config work since we have ~16k devices on the local symm and another ~20k on a remote symm with an SRDF/A link

Sometimes I'm tempted to skip it myself!

And I was thinking 10k was a lot... I feel tiny all of a sudden...

There is no harm at all.

Do it frequently.

Well, when you have mainframe mixed in with the Open Systems, and the mainframe guys still insist on using MOD-3 devices for most of their capacity... it adds up to a lot of devices. On our Prod array they account for about 20% of our capacity and about 80% of the devices (by count).