Hi All, we are on Oracle Exadata image version 19.2.9.0 but the database is
still on 11.2.0.4. It's a X5-2 , half RAC machine with ~7 cell servers and
~41TB of flash cache(i.e. ~5.9TB of flash cache per cell disk, write back).
Its only one database resides in this exadata machine.
Just to give a background, many times we encounter situations where the
flash cache response time increases to ~10ms for the small reads and impact
the oltp workload, and it happens mainly when we have a lot of full
scan/smart scans happen from the warehousing type workload at same time.
And during this the flash disk Io utilization reaches up to ~80% with large
reads showing ~30K IOPS. Similarly another exadata box on X3-2 with FULL
RAC with multiple databases mounted on it though and ~20TB flash
cache(Write through), and we are seeing a spike in hard disk response/IO
utilization but not such spike in flash disk response or IO utilization.
Now we are definitely working on making the application queries better but
as part of tech refresh, the infra team already has a plan to move to a new
exadata box , so management is asking, if having a full rack or additional
storage cell servers added, would be helpful in making the above situation
better? Or say having more flash cache allocated with the same number of
cell servers will help us create some more capacity? Want to understand
experts' thoughts on the same.
Regards
Lok
