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I have 2 OWC Mercury Elite Pro Dual Drive enclosures each with two 2 Tb drives.
I have set them both to contiguous RAID's via Apple's Disk Utility in Leopard (10.5.8). My question is can I now set the two pairs to RAID 1 mirror each other with Disk Utility WITHOUT erasing them both. I can't seem to find this info on Apple Support so I thought I'd ask here. The goal is to have a 4TB drive with a 4TB mirror.
FYI: Setting the switches on both these units (according to OWC instructions) fails to produce the hardware RAID configurations they should. Both enclosures are out of warranty (surprise!)
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When you create a new RAID, you wipe the old one.
The data will be gone.
...Also, while you can get away with RAIDing separate external devices, you shouldn't do it. If one device spins up a second late, that breaks the RAID.
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I'll second the "don't do it"
It is a horrible idea.
And, yes, you would have to erase.
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...OTOH, you could use Carbon Copy Cloner to make a scheduled nightly backup from one device to the other.
Then you would have a backup that's almost as good as a mirror with no need to fret about re-RAIDing your drives.
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Depending on the model - those can be setup as hardware spans or RAID 0 or RAID 1... You could then use Disk Utility to RAID 1 them (if you did spans) or Span them if you did RAID 1s and have the redundancy I think you're seeking while avoiding RAID 0 risks.
You can't create a software raid volume with other OS X controlled software raid volumes.
feel free to PM me if like to get in touch with an OWC tech that can dive deeper / help with more details and assistance.
Thanks.
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Onamuji wrote:
...OTOH, you could use Carbon Copy Cloner to make a scheduled nightly backup from one device to the other.
Then you would have a backup that's almost as good as a mirror with no need to fret about re-RAIDing your drives.
I would do this.
Or, you could put them all in one RAID box, if they're all the same 2TB drives.
http://eshop.macsales.com/item/OWC/M3QX2KIT0GB/
Jeff
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Thanks guys. I kind of figured they would all get errased first so that's not going to happen. I think I'll just do the CCC nightly backup, that seems to fit exactly what I want.
OWC Larry, thanks for the support offer. These are two of the older style Triple interface (FW 800, FW400,USB 2) cases with the 934 chipset. Unless I'm doing something wrong, the three DIP switches that you use to change the RAID type don't seem to work except for all off (Independant). JBOB only shows one drive for 2TB total as does the RAID 0 option.
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If it's really from way back... it might be from before over 2TB volume support. There is a separate jumper for setting for over 2TB as it takes away some legacy support for booting on Pre-Intel Macs to go over 2TB.
If I had a serial - can zone in to the exact unit and give an informed answer. but yes- a change to RAID mode will wipe the data.
Jack D. wrote:
Thanks guys. I kind of figured they would all get errased first so that's not going to happen. I think I'll just do the CCC nightly backup, that seems to fit exactly what I want.
OWC Larry, thanks for the support offer. These are two of the older style Triple interface (FW 800, FW400,USB 2) cases with the 934 chipset. Unless I'm doing something wrong, the three DIP switches that you use to change the RAID type don't seem to work except for all off (Independant). JBOB only shows one drive for 2TB total as does the RAID 0 option.
