We recently moved our busiest two 11gR2 EE databases (about 1TB each) from an
X4 ODA to an X5. It was via switchover to physical standbys, so we hadn't been
using - didn't really know about (no Flash Cache SSDs in X4s) - Database Smart
Flash Cache. Last weekend we were able to configure each DB (one per node on
the X5 ODA) to have 192GB Flash Cache (out of 512GB total available in the ODA).
Well, it's been better than Christmas! We've been marveling at the HUGE overall
performance improvement we see. The main App hitting one of the DBs is a COTS
Student Information System, hit by all of our 12,000 or so teachers and staff.
There were a bunch of Selects in the App's code that would drive load averages
to 200 - 400% periodically during the day. Now we rarely see load averages
approaching 100%, usually staying around 25%. StatsPac reports show the
dramatic differences in waits, as well as the SQLs found to be hogs.
My question ... Is there a way to get visibility into the flash cache to see
what's in there? Since this is 11g, the 12c-only V$FlashFileStat view is not
available and V$Sess_IO only has the session level Optimized_Physical_Reads
column. None of the SGA-related views that I've found have info. about the
flash cache. Mr. Google and MOS haven't helped either.
Any way to see what's going on in the Flash Cache?
Thanks.
--
Jack C. Applewhite - Database Administrator
Austin I.S.D. - MIS Department
512.414.9250 (wk)
I can't help about the shape I'm in,
I can't sing, I ain't pretty and my legs are thin.
But ... -- "Oh Well" F.M.
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