>>>>> "Jake" == Jake Anderson <ya...@vapourforge.com> writes:
Jake> On 03/09/09 16:09, Martin Visser wrote: >> Jake, >> >> Most of thenumbers you are showing are just the clocked speeds on >> busses and cables. Jake> actually no they are benchmarked sustained and average transfer Jake> rates for the devices. sata "2" line speed is 3gbit, with Jake> overhead it will saturate at 250mbyte/sec the hdd's min transfer Jake> rate is 60mbyte/sec and max is 160. >> Certainly the components can clock at those speeds, but the biggest >> issue with lower-end components is whether they can actually feed >> and sustain data at that rate, and how well they handle contention >> for resources. Generally this comes down to size of buffers, and >> whether have fast or wide enough processors at those interface >> points. >> Jake> They aren't really "lower end components" There is little Jake> difference in performance between SATA and SAS these days. Jake> PCI/PCI-X will sustain those transfer rates by design, the cards Jake> themselves are being little more than a slightly bent pipe so Jake> there should be no real bottleneck there. We've seen some problems with some SATA port multipliere, that don't allow more than one drive at a time to be working --- effectively slowing the transfer rate to that of a single spindle. I don't know if the ones these people are using have that problem. -- Dr Peter Chubb http://www.gelato.unsw.edu.au peterc AT gelato.unsw.edu.au http://www.ertos.nicta.com.au ERTOS within National ICT Australia -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
