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, 2-socket by 4 thread, 3 GHz with two AOC MV8 boards and 800 MHz (iirc) fsb connecting 16 GB RAM that runs at equal speed to fsb. Cheap 7200 RPM Seagate SATA half-TB disks with 32MB cache.
Is this increase explicable / expected? The throughput calculator sheet output I saw seemed to forecast better iops with the striped raidz vdevs and I'd read that, generally, throughput is augmented by keeping the number of vdevs in the single digits. Is my superlative result perhaps related to the large cpu and memory bandwidth? Just throwing this out for sake of discussion/sanity check.. thx jake -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
