> >> Unless you actually want to test writing dirty pages, and I have seen > >> a kernel bug where flushing dirty pages was slow, but then you should > >> also time a 'sync': > >> time dd if=/dev/zero of=/mnt/point/file bs=1M count=1000 && time sync > >>
That is part of the timing sequence, yes. > > Conrad> Mostly I wonder if it is atall possible to get such speeds > Conrad> over QDR. Are you in a position where you could perhaps run a > Conrad> "cp" followed by "sync" on an infiniband attached storage > Conrad> system? > > Absolutely, Infiniband is fast, and QDR should be insanely fast, and > low low latency as well, which is it's primary metric. > Do you have any comparative values for this particular sequence of commands? > > But can we go back and look at your system again? What OS, what > hardware, what filesystem, are you using LVM? How is the array RAID > setup, or is it not using RAID on the hardware end? sure. on the storage server gentoo, lvm, md raid 10, 512k chunks, 3.2.8 kernel with in-tree SRP on the remote server OS = debian, 3.2.8 kernel, intree SRP, > > Have you tried using 'fio' the Flexible IO Tester to run your tests > instead? yes I did, the results were inconclusive though (to me at least) ;) Conrad _______________________________________________ Tech mailing list [email protected] https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
