Harry Putnam wrote:
Erik Trimble <erik.trim...@oracle.com> writes:
Do you think it would be a problem having a second sata card in a PCI
slot? That would be 8 sata ports in all, since the A-open AK86
motherboard has 2 built in. Or should I swap out the 2prt for the 4
prt. I really only need 2 more prts currently, but would be nice to
have a couple still open for the future.
Your PCI bus bandwidth is shared, so it doesn't matter if you use 3 x
2port cards, or 2 x 4port cards (or, in your case, 1x2port +
1x4port). Performance is going to be virtually identical.
Thanks.
So performance with drop as number of drives increases?
Bus bandwidth is the limiting factor here (that is, the technology and
speed available to move data from the Host Bus Adapter to Main Memory).
In your case, with the severely limited amount of (PCI) bus bandwidth,
you'll reach the maximum performance level for your drives relatively
quickly - your 8-drive config will easily out-perform the available bus
bandwidth (in fact, 4 drives likely could fully utilize the bus).
As noted by Roy in another post, PCI is a share-bandwidth technology,
so having multiple cards in a system reduces the total usable bandwidth,
in the same manner that having multiple connections to an Ethernet Hub
reduces the general available bandwidth (contention between each card
for access to the PCI bus causes a reduction in the overall throughput).
In your case, you've likely already got bus contention with the
integrated peripherals competing for the PCI slot's bandwidth, so the
difference in performance between a 2 4-port cards and a 1 8-port card
isn't going to be realistically noticeable.
For more modern PCI-Express layouts, x4 and x8 lane setups can easily
handle 20 or more hard drives without becoming saturated.
The bottom line here is that you've got a Chevy Nova of a PC, and it ain't ever
going to perform like a Mustang, let alone a Ferrari, so don't worry too much
about the performance issues of your parts - the system bottlenecks are
elsewhere, and not fixable (short of replacing the entire MB/CPU/ etc).
Personally, I'd be surprised if you could get it to keep up with a fully-utilized Gigabit ethernet interface. However, it should have no problem keeping up with the Fast Ethernet interface on the MB.
--
Erik Trimble
Java System Support
Mailstop: usca22-123
Phone: x17195
Santa Clara, CA
Timezone: US/Pacific (GMT-0800)
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