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Oracle Tips by Burleson |
The Problem of Super-large Disks
Over the decades, disk manufacturers continued to make disk devices
larger, ignoring the bandwidth limitations imposed by locating all
of the data storage on a single device. As of 2005, it is very
difficult to purchase a disk spindle that is less than 100
gigabytes, and this causes disk I/O bandwidth issues at two levels.
- Bandwidth limitations within the disk as a result of
excessive read-write head movement
- Controller bandwidth limitations
Today’s super-large disks allow the Oracle DBA to place an entire
database onto a single pair of mirrored devices. This imposes a
severe data transmission bottleneck, especially when concurrent
requests for data are made for data on different cylinders. This can
cause the disk to shake like an unbalanced washing machine in the
spin cycle, and seriously impede the ability of Oracle to deliver
information to an application.
The above book excerpt is from:
Oracle RAC
& Grid Tuning with Solid State Disk
Expert Secrets for High Performance Clustered Grid Computing
ISBN:
0-9761573-5-7
Mike Ault, Donald K. Burleson
http://www.rampant-books.com/book_2005_2_rac_ssd_tuning.htm |
