Is it worth raiding 2x Hitachi 3TB 7200rpm Deskstars?

[sparkie7]

ok thanks, not seen these dock before. and as for the card, will this one do?

http://eshop.macsales.com/item/NewerTech/MXPCIE6GRS/

Finally, how about I RAID 0 both drives at 1TB volumes through out. I get double the performance whilst still getting the capacity. And back up regularly to mitigate the risk factor. Will this still pose simultaneous access issues?

 

[khollister]

ok thanks, not seen these dock before. and as for the card, will this one do?

http://eshop.macsales.com/item/NewerTech/MXPCIE6GRS/

Finally, how about I RAID 0 both drives at 1TB volumes through out. I get double the performance whilst still getting the capacity. And back up regularly to mitigate the risk factor. Will this still pose simultaneous access issues?

That eSATA card is fine

TO be effective, the scratch disk has to be on a physical disk (not a partition) DIFFERENT from the disk(s) your data and OS swap file is on. The disk heads can only be in one place at a time.

I suggested what to do in my opinion, but it's your computer - feel free to do whatever you want.

 

[nanofrog]

ok thanks, not seen these dock before. and as for the card, will this one do?

http://eshop.macsales.com/item/NewerTech/MXPCIE6GRS/

Finally, how about I RAID 0 both drives at 1TB volumes through out. I get double the performance whilst still getting the capacity. And back up regularly to mitigate the risk factor. Will this still pose simultaneous access issues?

khollister is offering the best solution using the hardware already mentioned (past this, you'll spend more money; additional disks, or worse; additional hardware as well, and if it involves a hardware RAID solution, be prepared to spend as much or more than you spent on the computer ).

And Yes, if you use partitions (one for scratch, one for data), you will run into the simultaneous access issue. It's down to simple physics; the heads are all on the same armature operated by a single servo, so they cannot be in two different locations at the same time.

So you'd be better off using separate disks or RAID sets independent of one another (scratch = 1 physical disk/set, while primary data = totally separate disk/set).

What you decide to do is your choice, but you will be disappointed if you go ahead with what you're asking about.

 

[sparkie7]

ok thanks guys. i'll heed your advice and just use them as normal data & back up drives with partitions unRAIDed. their too big together as one big RAID 0. 6TB is just too big for my needs.

so my option now is to utilise the spare optical bay. after some reading i can get this: http://eshop.macsales.com/item/OWC/MM352A52MP/

to install 2x SSDs (probably 2x Vertex 3 60GB). i can then use the two unused SATA ports on the logic board to connect them up. the only thing is the power..

i have a ATI 4870 and 3870 installed, and the 4870 uses the 2nd power source from the optical reserve. is there a way to get power to the 2x SSDs in the spare optical bay? splitter perhaps?

 

[nanofrog]

ok thanks guys. i'll heed your advice and just use them as normal data & back up drives with partitions unRAIDed. their too big together as one big RAID 0. 6TB is just too big for my needs.

so my option now is to utilise the spare optical bay. after some reading i can get this: http://eshop.macsales.com/item/OWC/MM352A52MP/

This would work just fine.

to install 2x SSDs (probably 2x Vertex 3 60GB). i can then use the two unused SATA ports on the logic board to connect them up. the only thing is the power..

i have a ATI 4870 and 3870 installed, and the 4870 uses the 2nd power source from the optical reserve. is there a way to get power to the 2x SSDs in the spare optical bay? splitter perhaps?

You could probably get a splitter, but the safer thing to do (and eventually, would need with newer GPU cards), is use an additional PSU externally (need to jump the green and black wires to get it to turn ON) as a means of providing more power.

The reason is, you could easily draw too much power off of the PSU rails and burn it up (not that many in the MP's PSU, nor do we know how they're actually distributed in the MP).

BTW, the HD3870 probably draws ~90W, and the HD4870 draws ~170W. PCIe slots can deliver 75W each, so you might be able to use a PSIG Y Splitter to feed both cards (one of the GPU cables on the logic board to the splitter, then one end to both cards).

Then use a Molex to 2x SATA power splitter to feed the SSD's.

Or get a Molex to 2x Molex splitter, and use that to both what you already have, and a Molex to 2x SATA power splitter to feed the SSD's (they don't draw that much power).

So you have multiple paths you can take.

 

[sparkie7]

Thank you for the feedback

You could probably get a splitter, but the safer thing to do (and eventually, would need with newer GPU cards), is use an additional PSU externally (need to jump the green and black wires to get it to turn ON) as a means of providing more power.

The reason is, you could easily draw too much power off of the PSU rails and burn it up (not that many in the MP's PSU, nor do we know how they're actually distributed in the MP).

I doubt I will invest in any more newer GPU cards on this MP. How would one fit/power to the MP via an additional PSU?

BTW, the HD3870 probably draws ~90W, and the HD4870 draws ~170W. PCIe slots can deliver 75W each, so you might be able to use a PSIG Y Splitter to feed both cards (one of the GPU cables on the logic board to the splitter, then one end to both cards).

I never thought of this. I think I saw two of these power outputs on the logic board. I could connect this to one of them as you say. With one to the HD3870 & the HD4870, and the other power connector solely for the HD4870 as it draws more power. Will this be enough to power both cards you think?

I'm based outside the US and Newegg don't ship internationally, so OWC is probably the option for me. I tried to search for it but could not find it. Do you know the equivalent part I'd need to order?

Then use a Molex to 2x SATA power splitter to feed the SSD's.

I found this on OWC, is this the same thing? http://eshop.macsales.com/item/Micro%20Accessories/SATAPAY/

Or get a Molex to 2x Molex splitter, and use that to both what you already have

I'm not sure but I found this on OWC, will this do? http://eshop.macsales.com/item/Belkin/F2N503/

Thanks again for all your help

 

[nanofrog]

I doubt I will invest in any more newer GPU cards on this MP. How would one fit/power to the MP via an additional PSU?

The additional PSU would have to exist externally of the MP, and you run the graphics power cables into the MP (say through an open PCI bracket or between the case and removable side panel).

I never thought of this. I think I saw two of these power outputs on the logic board. I could connect this to one of them as you say. With one to the HD3870 & the HD4870, and the other power connector solely for the HD4870 as it draws more power. Will this be enough to power both cards you think?

First of all, this particular splitter cannot plug into the MP's logic board, as those connectors aren't the same size (Apple chose smaller than standard connectors).

So the PSIG Splitter has to connect to one of the original Apple cables, which leaves you with 2x PSIG ends for plugging into cards, as well as the second 6 pin connector and associated Apple cable (= 3x PSIG ends total).

Now the Splitter cable ends; plug one into each graphics card (reduces the load on that particular logic board connector).

The remaining original Apple cable gets plugged into the HD4870.

It's all about balancing the load. Otherwise, you may end up drawing too much power from the connector you've attached the PSIG Splitter to.

I'm based outside the US and Newegg don't ship internationally, so OWC is probably the option for me. I tried to search for it but could not find it. Do you know the equivalent part I'd need to order?

The links were for reference only. Just find equivalents to them from sources that will ship to you (figured the photos of those cables would be helpful; pay close attention to the gender).

Fortunately, all of these cables are common, and should be easily found.

I found this on OWC, is this the same thing? http://eshop.macsales.com/item/Micro%20Accessories/SATAPAY/

I'm not sure but I found this on OWC, will this do? http://eshop.macsales.com/item/Belkin/F2N503/

Both are fine.

Now all you need is to find a source for the graphics card power splitter.

BTW, you don't have to order from OWC. These are common cables, and should be found at other sites closer to home (cheaper in the end, such as reduced shipping charges).

 

[sparkie7]

I'm thinking its just easier to run a power splitter from the spare optical bay connector using this http://eshop.macsales.com/item/Belkin/F2N503/

Will this fit/work? (sorry just want to be really sure i order the right cables, and hope I got all the heads matched up!)

Then just hook the 2x SSDs with this kit http://eshop.macsales.com/item/OWC/MM352A52MP/ Especially as the SSDs take much less power than the graphics cards.

Should work right?

Btw, any ideas why the OWC kit one SATA connector thats right angled and the other that's straight? -- seems a little strange, unless i'm missing something?

 

[nanofrog]

I'm thinking its just easier to run a power splitter from the spare optical bay connector using this http://eshop.macsales.com/item/Belkin/F2N503/

Will this fit/work? (sorry just want to be really sure i order the right cables, and hope I got all the heads matched up!)

It probably would, and is one of the options I mentioned earlier.

The problem is, we don't know which rail is which, or how much of a load is already on each. So it is possible to overload a rail.

As a result, I'd keep the load on the optical bay Molex source as low as possible = connect the graphics cable that will be attached to the Molex splitter to the HD3870, as it draws less power (graphics power cable you're already using).

Which would keep the HD4870 attached to the graphics power connectors on the logic board as I presume is already the case.

Btw, any ideas why the OWC kit one SATA connector thats right angled and the other that's straight? -- seems a little strange, unless i'm missing something?

So things fit properly.

They do a good job planning things out, and it will work. Just read the instructions (common sense should be enough, but the directions could save you some time).

 

[sparkie7]

It probably would, and is one of the options I mentioned earlier.

The problem is, we don't know which rail is which, or how much of a load is already on each. So it is possible to overload a rail.

As a result, I'd keep the load on the optical bay Molex source as low as possible = connect the graphics cable that will be attached to the Molex splitter to the HD3870, as it draws less power (graphics power cable you're already using).

Which would keep the HD4870 attached to the graphics power connectors on the logic board as I presume is already the case.

I had opened up and had a peep. Up in the optical bays, One bay used - as standard with  installed CD/DVD drive. Which has a spare power cable hanging off it which I have connected up to power the HD4870. On the logic board, one power connector powers the HD4870 (total of two power inputs) and the other one for the HD3870.

I thought the power draws were similar? HD3870 draws ~90W, and the HD4870 draws ~170W (ie 170 divided by 2 = 85), so shouldn't matter too much which power connectors?

But based on your above post sounds like I need to switch the one in the optical bay to the HD3870 and then have both on the logic board powered up to the HD3870.

Thanks again for all your help

 

[nanofrog]

I had opened up and had a peep. Up in the optical bays, One bay used - as standard with  installed CD/DVD drive. Which has a spare power cable hanging off it which I have connected up to power the HD4870. On the logic board, one power connector powers the HD4870 (total of two power inputs) and the other one for the HD3870.

I thought the power draws were similar? HD3870 draws ~90W, and the HD4870 draws ~170W (ie 170 divided by 2 = 85), so shouldn't matter too much which power connectors?

Remember, the PCIe slot provides up to 75W of power.

So it should be 90W - 75W = 15W off of the cable plugged into the HD3870. This is why it's best to use the Molex to 6 pin GPU adapter cable to this particular card, as it's the smallest load off of the Molex end (since we don't know the actual loads), rather than the hungrier 4870.

In the case of the HD4870, you get 170W -75W = 95W; divide by 2, and you've got 47.5W per. Draw all of this from the logic board's graphics power connectors.

The 6 pin graphics power connectors are also rated for a max draw of 75W. Any more, and you could damage the traces on the board (melt the Hot Air Leveling = layer of solder, and cause a short), even if the PSU could take draw prior to the short (actually happened before, so this isn't just academic).

But based on your above post sounds like I need to switch the one in the optical bay to the HD3870 and then have both on the logic board powered up to the HD3870.

Thanks again for all your help

Absolutely move it to the HD3870.

And you're welcome (what forums are for - users help one another).

 

[sparkie7]

Remember, the PCIe slot provides up to 75W of power.

So it should be 90W - 75W = 15W off of the cable plugged into the HD3870. This is why it's best to use the Molex to 6 pin GPU adapter cable to this particular card, as it's the smallest load off of the Molex end (since we don't know the actual loads), rather than the hungrier 4870.

In the case of the HD4870, you get 170W -75W = 95W; divide by 2, and you've got 47.5W per. Draw all of this from the logic board's graphics power connectors.

Ah, Great thanks for the info.

The 6 pin graphics power connectors are also rated for a max draw of 75W. Any more, and you could damage the traces on the board (melt the Hot Air Leveling = layer of solder, and cause a short), even if the PSU could take draw prior to the short (actually happened before, so this isn't just academic).

That's 75W per graphics power connector right? So x2 (on the logic board) = 150W max together?

Btw, do you the max power draw from the spare molex connector hanging off the optical drive?

Absolutely move it to the HD3870.

And you're welcome (what forums are for - users help one another).

Will do, when I get all the cables, bay and SSDs together. Will leave as is in the interim.

Again, Thanks very much for your patience and help. It's much appreciated

 

[nanofrog]

That's 75W per graphics power connector right? So x2 (on the logic board) = 150W max together?

Correct.

Btw, do you the max power draw from the spare molex connector hanging off the optical drive?

No official documentation on it AFIAK.

So figure worst case, and base it off of what the ODD would draw during startup, not what the cable itself could technically handle (figure ~40W at best).

 

[sparkie7]

Correct.


No official documentation on it AFIAK.

So figure worst case, and base it off of what the ODD would draw during startup, not what the cable itself could technically handle (figure ~40W at best).

Great thanks again. Yeah, I tried to check for details the power on the optical but couldn't find any  published specs.

The Vertex 3 SSD power consumption are really low, only 3W (active) so with two hooked up that only 6W + 15W for the HD3870 = only 21W so it looks like an adequate setup.