While it wont explain the drop from 55-44Mbyte/second I think ~50MByte/second is pretty good considering such a latency-bound test such as single threaded dd writing one 1024byte block at a time. I would either run dd with a much much larger blocksize, or with many concurrent dd in parallell in order to reduce the cost-per-byte-in-latency to get throughput numbers instead of latency-bound numbers. On Sat, Jul 26, 2008 at 4:46 AM, Richard Sharpe <realrichardsharpe at gmail.com> wrote: > On Wed, Jul 2, 2008 at 2:01 PM, Richard Sharpe > <realrichardsharpe at gmail.com> wrote: >> Hi, >> >> I am testing some configurations I have laying around here at work while >> waiting for our new hardware to arrive. >> >> I set up one system, a 1U with 2GB of memory and a Xeon (speed not really >> relevant to this) and GigE as a target and set up a virtual disk via iSCSI. >> >> Then on another system, an old DELL, I set up the initiator, and ran: >> >> dd if=/dev/zero of=/dev/sda1 bs=1024 count=1000000 >> >> and I got a throughput of 10.5-10.8MB/a while consuming around 10-12% of the >> CPU on the target (shown via top). > > OK, I have shifted to faster machines (a couple of 1U Tyan B5211s with > Quad core Xeon X3230 @ 2.66GHz and jumbo frames ...) > > I get around 58.6MB/s with 819MB but it drops to 44-45MB/s with 8GB > files (with a variety of block sizes (4096, 8192, 16384). > _______________________________________________ > Stgt-devel mailing list > Stgt-devel at lists.berlios.de > https://lists.berlios.de/mailman/listinfo/stgt-devel > |