 |
|
Oracle Tips by Burleson |
Oracle Disk I/O Tuning
Chapter 5:
Configuration of Automated Storage Management
Load balancing (SAME)
Oracle has been
promoting the concept of SAME – Stripe and Mirror Everything which
aimed at using the full I/O capacity of the all the disks. Many
database users have implemented “SAME sets”, each of about 4
mirrored disk pairs. However the SAME functionality does not
completely eliminate the disk imbalances. There are different types
of files where the IO activity is not uniform, and the configuration
of SAME is not the cure for all IO ills.
ASM goes a step forward,
in balancing the IO activity. Rebalancing distributes file data
evenly across all the disks of the ASM Disk Group. ASM automatically
rebalances a disk group whenever disks are added or dropped. ASM
ensures that a file is evenly spread across all disks in a disk
group when the file is allocated, so rebalancing is not required
except when the storage configuration changes. With the I/O balanced
whenever files are allocated and whenever the storage configuration
changes, you never need to search for hot spots in a disk group and
manually move data to restore a balanced I/O load. It also allows
the addition of disks online. There are extra background processes
that conduct the rebalancing activity in a non-intrusive way.
Thus the ASM makes
manual load balancing unnecessary, because the dynamic rebalancing
overcomes the major drawback of SAME. When new disks are added to a
disk group, rebalancing happens automatically without an outage.
The above text is
an excerpt from:
Oracle Disk I/O Tuning
Disk IO Performance & Optimization for Oracle
Databases
ISBN
0-9745993-4-4
by Mike Ault
Oracle Consulting
Services
Burleson
Oracle Consulting offers Senior Oracle consultants which are available for all
areas of Oracle support. Common Oracle consulting support activities include
short-term Oracle tuning, Oracle database troubleshooting, Oracle9i and
Oracle10g migration,
Oracle9iAS App Server
consulting, Oracle design reviews and
Oracle requirements evaluation support. Oracle support and Oracle consulting
services are priced by the hour, so you only pay for what you need. These
one-time Oracle consulting services commonly include:
-
Answering
questions from your Oracle DBA technical staff
-
Repairing down
production Oracle database systems
-
One-time
Oracle tuning evaluation
-
Guru support
for your Oracle DBA
-
Installation
of Oracle application packages
For more
information, please visit
www.oracle-training.cc.
|
