At 2003-03-11T18:41:12Z, Ron Johnson <ron.l.johnson@cox.net> writes: > Why wouldn't you get parallel reads, especially if you do async IO? I guess a better example would be when two files are accessed, and each has blocks that physically reside on the same two drives. Imagine that both files are accessed randomly and concurrently (think multiple database instances). In this case, it could very well happen that blocks from file1 (f1a, f1b) and file2 (f2a, f2b) are being read simultaneously. In this case, both drives are jumping back and forth between f1a/f2a and f1b/f2b. Imagine, instead, that file1 and file2 are on a mirror. The RAID system could converge on the situation where the first drive is "dedicated" to file1, and the second is "dedicated" to file2. I don't think this is a particularly unlikely scenario. -- Kirk Strauser In Googlis non est, ergo non est.
Attachment:
pgpPD7dWncSK_.pgp
Description: PGP signature