On Jun 11, 2009, at 1:39 PM, Tom Buskey wrote: > > > On Thu, Jun 11, 2009 at 1:27 PM, Thomas Charron <twaf...@gmail.com> > wrote: > On Thu, Jun 11, 2009 at 1:22 PM, <bruce.lab...@autoliv.com> wrote: > > Thomas Charron <twaf...@gmail.com> wrote on 06/11/2009 12:30:16 PM: > >> Another trick I've used when dealing with massive amounts of > data is > >> to use 'fast' media, aka, flash instead of a hard drive. Memory > >> mapping to this sort of media worked well for me. > > I would love to run a fast drive. However, all I have available > is NFS on > > gbit e-net. My sustained file write rate is ~45MiB/sec. (377.5e6 > > bits/sec) > > That sounds moderately ok until one realizes the file size (one > chunk) is > > ~4.5GiB. > > You don't have physical access to the machine? Even a USB can give > better performance then that. > > Does it?
Typically, no. USB sucks horribly for disk I/O. > USB 2.0 is 480 mbits/s which is probably close to 48 MB/s. > 45 MB/s on gigabit ethernet isn't too bad. (480 Megabit/second) * (1 Megabyte/8 Megabit) = 60 MB/s. But in practice, you'll rarely see much better than about 30MB/s, because all bus arbitration is done by the host cpu, which is grossly inefficient. FireWire or (even better) eSATA blows USB out of the water for external disk I/O performance. -- Jarod Wilson ja...@wilsonet.com _______________________________________________ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
