Re: unable to produce sequential writes to redo log

"Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> writes:
| Redo writes in in a multiple of what it
| considers to be the device driver block
| size (which is often 1K, sometimes 512
| bytes).
|
| Consequently you can do a 1K redo write
| which requires the file system to do a 4K
| or 8k read into which the 1K change is
| written.

that makes a LOT of sense given that i'm seeing a 1:6 or 1:7 ratio between reads and writes.

i'm surprised this isn't (more of) a FAQ item given how badly it kills you...

thanks!
--

  Paul M. Aoki         | Computer Science Division, EECS #1776
  aoki_at_CS.Berkeley.EDU | University of California
                       | Berkeley, CA 94720-1776 USA