On Wed, Dec 17, 2014, at 10:26 PM, Dan Egli wrote: > On December 16, 2014, [email protected] wrote: > > > i did an experiment a couple years ago where i booted a > > > windows machine off an iscsi target connected over gigabit ethernet. > > > loading games and regular desktop usage was almost as good as if the > > > hard drive was connected to the local system. > > > > That's actually impressive. I didn't think Gigabit went that fast. I > recall > reading somewhere that a base rule of thumb when speaking of speeds over > the network was to take the advertised speed and quarter it to get the > actual usage speed. 25MB/sec isn't very fast at all these days. Even > mechanical SSDs frequently read at 150MB/sec and write at 100MB/sec if > the benchmarks I've seen are any indication. I may have to do some tests.
i don't know that i've ever heard that rule of thumb before. if talking about systems connected to the same switch and assuming its a decent switch, then there isn't any hardware reason you shouldn't be able to get the full speed of the link. its most likely a software issue if you aren't. things should also scale nicely to multiple switches with a little planning. i wouldn't necessarily expect good performance with doing iscsi over the internet but locally it should work well. also, if you have equipment that supports it, you can try using jumbo frames. that will reduce cpu overhead since its possible to fit multiple 4k requests in a single packet verses needing 3 packets for a single 4k request. i have no idea what a "mechanical SSD" is. :) yes, there are hard drives that can do *sequential* io at greater than 100MB/sec. sequential io is usually the exception for desktop traffic. those are usually a much more random io pattern. either way, you probably already have gear to try it with gigabit interfaces so might as well give it a try. if you find it doesn't have the performance, then look for an alternative. mike /* PLUG: http://plug.org, #utah on irc.freenode.net Unsubscribe: http://plug.org/mailman/options/plug Don't fear the penguin. */
