> Brain damage seems a bit of an alarmist label. While you're certainly right > that for a given block we do need to access all disks in the given stripe, > it seems like a rather quaint argument: aren't most environments that > matter trying to avoid waiting for the disk at all? Intelligent prefetch > and large caches -- I'd argue -- are far more important for performance > these days.
The concurrent small-i/o problem is fundamental though. If you have an application where you care only about random concurrent reads for example, you would not want to use raidz/raidz2 currently. No amount of smartness in the application gets around this. It *is* a relevant shortcoming of raidz/raidz2 compared to raid5/raid6, even if in many cases it is not significant. If disk space is not an issue, striping across mirrors will be okay for random seeks. But if you also care about diskspace, it's a show stopper unless you can throw money at the problem. -- / Peter Schuller PGP userID: 0xE9758B7D or 'Peter Schuller <[EMAIL PROTECTED]>' Key retrieval: Send an E-Mail to [EMAIL PROTECTED] E-Mail: [EMAIL PROTECTED] Web: http://www.scode.org
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