Boot Mac OS X off external drive?

[Raima]

I Got an external raid enclosure that consists of 4 x 1.5TB HDDs configured in raid 5. Is it possible to use the external raid enclosure as the start up disk on an iMac i7 and use the internal drive as a time machine backup drive?

I'm just wondering if this is possible?

[spinnerlys]

Theoretically and practically yes, but as the fastest interface on your Mac is the Firewire 800 port, you won't experience any speed advantages the RAID might offer you, if that is what you are after.

[Raima]

Theoretically and practically yes, but as the fastest interface on your Mac is the Firewire 800 port, you won't experience any speed advantages the RAID might offer you, if that is what you are after.

The external enclosure will be connected via firewire 800. How would this compare to the internal sata 300 connection?

[spinnerlys]

The external enclosure will be connected via firewire 800. How would this compare to the internal sata 300 connection?

FW 800 speed: 65 - 75MB/s
S-ATA 3.Gbps speed: 286MB/s

via search engine of your choice:
http://macperformanceguide.com/Storage-Drive-SATA-vs-Firewire.html


And this is just S-ATA 1.5Gbps:
http://macperformanceguide.com/images/graph-eSATA-vs-FW800-MacPro.gif

[Raima]

Oh so firewire is 800 megabits transfer, not 800 megabytes transfer?

Are there are disc benching utils available on the mac? I wouldn't mind running the test and giving the enclosure a bit of a work out.

[spinnerlys]

Oh so firewire is 800 megabits transfer, not 800 megabytes transfer?

Are there are disc benching utils available on the mac? I wouldn't mind running the test and giving the enclosure a bit of a work out.

Yes. As USB 2.0 does not transfer with 480MB/s, but with 480 Mbit/s, which it does not do either anyway.

S-ATA 1.5Gbps and S-ATA 3.0 Gbps, and soon S-ATA 6.0 Gbps, also use bit as data transfer measurement.


Disk Benchmarking tools:

AJA System Test found here: http://www.aja.com/products/software/

and XBench.

[Raima]

You were spot on with the Firewire 800 results. I'm getting inconsistent results with the SSD tho. The performance degrades as the number of tests increase.