On Tue, 6 Jan 2009, Jacob Ritorto wrote: > My OpenSolaris 2008/11 PC seems to attain better throughput with one > big sixteen-device RAIDZ2 than with four stripes of 4-device RAIDZ. > I know it's by no means an exhaustive test, but catting /dev/zero to > a file in the pool now frequently exceeds 600 Megabytes per second, > whereas before with the striped RAIDZ I was only occasionally > peaking around 400MB/s. The kit is SuperMicro Intel 64 bit, > > Is this increase explicable / expected? The throughput calculator
This is not surprising. However, your test is only testing the write performance using a single process. With multiple writers and readers, the throughput will be better when using the configuration with more vdevs. It is not recommended to use such a large RAIDZ2 due to the multi-user performance concern, and because a single slow/failing disk drive can destroy the performance until it is identified and fixed. Maybe a balky (but still functioning) drive won't be replaced under warranty and so you have to pay for a replacement out of your own pocket. Bob ====================================== Bob Friesenhahn bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
