Hi all
I'm thinking of adding at least one SAS expander to my setup, as I am currently using 4 x LSI cards - and therefore 4 x PCI-E 2.0 slots - to run 28 x 2TB SATA3 drives. I know that I can put more drives on fewer cards without losing performance, but as I have a low-profile case I can't use 4-port LSI cards as they're all full-height. Unless I cut a hole in my chassis roof which stupid as it sounds I may actually consider...
I'd much rather get an expander or two. But then my problem is that most of the cheap SAS expanders I can find on eBay require a PCI-E slot for power. Which rather defeats the object; my aim is to free up PCI-E slots, not use them to power SAS expanders! I know it's possible I could get one expander that would free up two of my slots, so that would still be a net gain. But I would really prefer to have access to all the freed slots, not have them 'wasted' providing only power.
I'd also like more flexibility in where I can physically locate any expander.
There are expanders that take 4-pin molex power, and that would be perfect. But so far I can't find any cheap ones available to the UK. The few that I have found (one IBM, one Chenbro) are much more expensive than the ubiquitous HP expanders flooding eBay: I can get an HP 3GB/s expander for £25, whereas an IBM or Chenbro is £100+.
So I was wondering if there was any way to make an adapter that would power a PCI-E card? Like maybe I could rip a PCI-E slot off an old motherboard, and solder up some wires to a 4-pin Molex plug somehow?
I am sure it's going to work out to be far more complicated than that.. for one thing the soldering is probably going to be hard, but maybe there's an even bigger problem. It occurred to me that maybe it can't work because it will expect more than just 12V power? Maybe it actually has to talk a protocol to the motherboard, even when it only needs power? I was hoping that I'd find that some of the PCI-E pins are directly wired to 12V / 5V / 3.3V (I haven't yet checked what voltages are sent), but maybe it's not nearly that simple.
The more I think about it the more I think there's a million reasons why this could never work, but I'd be grateful if anyone has any thoughts? At the least a firm "you're crazy, that's impossible" would enable me to move on to weighing up the other options
Thanks
I'm thinking of adding at least one SAS expander to my setup, as I am currently using 4 x LSI cards - and therefore 4 x PCI-E 2.0 slots - to run 28 x 2TB SATA3 drives. I know that I can put more drives on fewer cards without losing performance, but as I have a low-profile case I can't use 4-port LSI cards as they're all full-height. Unless I cut a hole in my chassis roof which stupid as it sounds I may actually consider...
I'd much rather get an expander or two. But then my problem is that most of the cheap SAS expanders I can find on eBay require a PCI-E slot for power. Which rather defeats the object; my aim is to free up PCI-E slots, not use them to power SAS expanders! I know it's possible I could get one expander that would free up two of my slots, so that would still be a net gain. But I would really prefer to have access to all the freed slots, not have them 'wasted' providing only power.
I'd also like more flexibility in where I can physically locate any expander.
There are expanders that take 4-pin molex power, and that would be perfect. But so far I can't find any cheap ones available to the UK. The few that I have found (one IBM, one Chenbro) are much more expensive than the ubiquitous HP expanders flooding eBay: I can get an HP 3GB/s expander for £25, whereas an IBM or Chenbro is £100+.
So I was wondering if there was any way to make an adapter that would power a PCI-E card? Like maybe I could rip a PCI-E slot off an old motherboard, and solder up some wires to a 4-pin Molex plug somehow?
I am sure it's going to work out to be far more complicated than that.. for one thing the soldering is probably going to be hard, but maybe there's an even bigger problem. It occurred to me that maybe it can't work because it will expect more than just 12V power? Maybe it actually has to talk a protocol to the motherboard, even when it only needs power? I was hoping that I'd find that some of the PCI-E pins are directly wired to 12V / 5V / 3.3V (I haven't yet checked what voltages are sent), but maybe it's not nearly that simple.
The more I think about it the more I think there's a million reasons why this could never work, but I'd be grateful if anyone has any thoughts? At the least a firm "you're crazy, that's impossible" would enable me to move on to weighing up the other options
Thanks