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Oracle Tips by Burleson |
Monitoring the Diskless Database
Currently, DBAs spend an inordinate amount of time
worrying about disk I/O, backups, and other topics that with the
advent of a diskless Oracle environment will simply cease to exist. As
more of the Oracle environment is virtualized, the monitoring has to
change to more CPU cycle monitoring and effective use of CPU
resources. This trend can already be identified with the larger
footprint being taken by such topics as CPU costing. Soon, query cost
will be counted not in terms of I/O to a disk but in CPU ticks and
memory cycles.
What will be eliminated?
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Monitoring the cache: It will be automatically
sized and tuned for the current working set only.
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Monitoring I/O speeds: Transfers will be at
near memory speeds.
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Monitoring for contention: With no moving
parts and hence greatly reduced latency, the SSD technology
increases bandwidth by several orders of magnitude.
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Monitoring redo logs: They will simply be
memory areas to be sized according to retention needs only.
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Monitoring undo segments: These will also
become memory structures
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Monitoring backups: The SSD technology backs
itself up. Offline backups of the backing store will not affect
database performance.
The DBA’s job as it is known today will undergo a
profound change with more focus on tuning and optimization than
worrying with physical hardware and backups.
But What About Now?
All of this information on improvements in the
future is great, but what about now? What about the DBA that gets a
RamSAN system? Does his job have to change? No. All monitoring that
is done now can be done against the RamSAN system. The SSD is treated
identically to a standard disk drive.
This means all of the DBA’s scripts will still
function as they always have. Monitoring tools will still act the
same, but of course, they will report much better performance.
Changing memory sizes should be done in a controlled fashion by
reducing cache memory and testing performance until peak performance
is reached. Preliminary testing shows the need to establish a working
set size System Global Area (SGA) database
cache which will vary from database to database.
The
above book excerpt is from:
Oracle
Solid State Disk Tuning
High Performance Oracle
tuning with RAM disk
ISBN
0-9744486-5-6
Donald K. Burleson & Mike Ault
http://www.rampant-books.com/book_2005_1_ssd.htm
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For more details and scripts, see my new book "
Oracle
Tuning: The Definitive Reference", over 900 pages
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You can buy it direct from the publisher for 30%-off and get
instant access to the code depot. |
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