William Loewe wrote: > Hello, > > I'm using a Sun Fire X4500 "Thumper" and trying to get some sense of the best > performance I can get from it with zfs. > > I'm running without mirroring or raid, and have checksumming turned off. I > built the zfs with these commands: > > # zpool create mypool disk0 disk1 ... diskN > # zfs set checksum=off mypool > # zfs create mypool/testing > > When I run an application with 8 threads performing writes, I see this > performance: > > 1 disk -- 42 MB/s > 2 disks -- 81 MB/s > 4 disks -- 147 MB/s > 8 disks -- 261 MB/s > 12 disks -- 347 MB/s > 16 disks -- 433 MB/s > 32 disks -- 687 MB/s > 45 disks -- 621 MB/s > > I'm surprised it doesn't scale better than this, and I'm curious to know what > the best configuration is for getting the maximum write performance from the > Thumper.
When doing testing like this, you will need to make sure you are creating enough large I/O to be interesting. Unlike many RAID-0 implementations, ZFS will allocate 128kByte blocks across vdevs on a slab basis. The default slab size is likely to be 1 MByte, so if you want to see I/O spread across 45 disks, then you'd need to generate > 45 MBytes of concurrent, write I/O. Otherwise, you will only see a subset of the disks active. This should be measurable via iostat with a small period. Once written, random reads should exhibit more stochastic balancing of the iops across disks. The disks used in the X4500 have a media bandwidth of 31-64.8 MBytes/s, so getting 42 MBytes/s to or from a single disk is not unreasonable. -- richard _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
