MikeCurtis
HDforindies.com
Guys -
factors to consider:
FireWire 800 will be the fastest bus (unless a custom eSATA adaptor is made - anybody wanna jump on that, since that's the fastest possible bus?)
IF I recall correctly, FireWire 800 is good for about 50 MB/sec writes, 80 MB/sec reads on a G5, I'm presuming that a Mac Pro will be about the same (don't have my Octo Mac, but likely to order this week).
So 80 MB/sec is your max theoretical read speed from FW800.
The catch is, can you feed it that fast? We're coming from a couple of 160GB 2.5" drives - I'm thinking from past research these were good for about 20-40 MB/sec on the slower ones that had drop/crash protection, and about 30-50 MB/sec on the faster ones. I don't know what has changed since I originally did that research for myself, nor if they are still using the drives available when they started picking gear.
Note there's a range involved- 20-40 or 30-50 - that is because drives get slower as they fill up and write to the slower inner tracks. The falloff isn't linear - it holds pretty well and then drops towards the end.
This gets into a calculus, area-under-the-curve kind of a thing to calculate accurate average transfer rates. Barring that, let's go with the average presuming it is the slower of the drives - so 30 MB/sec, per drive. There's usually about a 10% hit for a RAID config under OS X, I dunno if that applies in general, but it seems plausible. So 27 MB/sec*2=54 MB/sec average....so FW800 will be limiting transfer rates for maybe half of the transfer. So 50 MB/sec*3.6=180 GB/hr. 320/180=1.778, which is getting pretty close to the hour fifty somebody else guessed. But 320 GB RAW capacity equals 296 GB formatted (presuming they use all the space - they may partition to get the "fast enough" part they need. )But then it'll slow down below that rate at some point, and the FW800 won't be the bottleneck, the speed with which data can come off the Red Drive will. So....based on LOTS of conjecture here...circa two hours? FW400 will definitely be slower, good for only about 35 MB/sec, that'd take about 3 hours 20 min to copy over 296 GB. And that presumes you're copying to another bus with no latencies - these times are just the "read the data off with no interruptions" numbers.
In short, we're ALL guessing, not knowing the actual drives used, the actual formatted capacity, latencies involved if writing to the same bus, the machine used, the hardware involved, etc.
factors to consider:
FireWire 800 will be the fastest bus (unless a custom eSATA adaptor is made - anybody wanna jump on that, since that's the fastest possible bus?)
IF I recall correctly, FireWire 800 is good for about 50 MB/sec writes, 80 MB/sec reads on a G5, I'm presuming that a Mac Pro will be about the same (don't have my Octo Mac, but likely to order this week).
So 80 MB/sec is your max theoretical read speed from FW800.
The catch is, can you feed it that fast? We're coming from a couple of 160GB 2.5" drives - I'm thinking from past research these were good for about 20-40 MB/sec on the slower ones that had drop/crash protection, and about 30-50 MB/sec on the faster ones. I don't know what has changed since I originally did that research for myself, nor if they are still using the drives available when they started picking gear.
Note there's a range involved- 20-40 or 30-50 - that is because drives get slower as they fill up and write to the slower inner tracks. The falloff isn't linear - it holds pretty well and then drops towards the end.
This gets into a calculus, area-under-the-curve kind of a thing to calculate accurate average transfer rates. Barring that, let's go with the average presuming it is the slower of the drives - so 30 MB/sec, per drive. There's usually about a 10% hit for a RAID config under OS X, I dunno if that applies in general, but it seems plausible. So 27 MB/sec*2=54 MB/sec average....so FW800 will be limiting transfer rates for maybe half of the transfer. So 50 MB/sec*3.6=180 GB/hr. 320/180=1.778, which is getting pretty close to the hour fifty somebody else guessed. But 320 GB RAW capacity equals 296 GB formatted (presuming they use all the space - they may partition to get the "fast enough" part they need. )But then it'll slow down below that rate at some point, and the FW800 won't be the bottleneck, the speed with which data can come off the Red Drive will. So....based on LOTS of conjecture here...circa two hours? FW400 will definitely be slower, good for only about 35 MB/sec, that'd take about 3 hours 20 min to copy over 296 GB. And that presumes you're copying to another bus with no latencies - these times are just the "read the data off with no interruptions" numbers.
In short, we're ALL guessing, not knowing the actual drives used, the actual formatted capacity, latencies involved if writing to the same bus, the machine used, the hardware involved, etc.
