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Can I Boot from a RAID 1 (mirror) in my G4?

1497 Views 10 Replies Latest reply: Oct 15, 2008 4:32 PM by Grant Bennet-Alder RSS
rezwits Calculating status...
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Oct 2, 2008 12:07 PM
I don't know where I read about this, but I am getting ready to redo one of my systems. Currently it has 2 identical 250GB Hitachies, which use Super Duper every Sunday to backup. I tried doing a RAID 0 back in like 2004 on a system that had 4x60GB. I found out through trial and error and then later reading that you can't boot from a RAID in a Power Mac G4. But like I said earlier I don't know where I read this, but someone stated I could boot from a RAID 1 (mirror) in my Power Mac G4. Is this true? or not? Is it possible to boot from a RAID 1 in a Mac G4 but not RAID 0?

Something tells me this isn't going to work. I have a 10% glimmer of hope that maybe it will just see the drive as a regular drive. This would really be great. If anyone knows the answer to this puzzle please feel free to let me know... thanks.

Laters...
MacBook, Mac OS X (10.5)
  • motsteve Level 2 Level 2 (225 points)
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    Oct 2, 2008 5:39 PM (in response to rezwits)
    I wish that someone would answer this one. I know zippiedy doo about raid and want to know more in a practical sense. Those man pages are putting me into la la land.

    Help! Japamac!
    iMac 20" and G4 Digital Audio, Mac OS X (10.5.5), G4 is MacOSX(10.4.11) iMac 3G ram G4 1G ram
  • japamac Level 7 Level 7 (24,390 points)
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    Oct 3, 2008 6:13 AM (in response to rezwits)
    Hi-

    RAID as a boot volume is supported in systems with OS X 10.3 or later.
    Mac OS X, Mac OS X Server: How to Use Apple-Supplied RAID Software

    A mirror RAID is definitely a safer boot volume than a striped RAID. Still, you need to keep SuperDuper!, and get a third drive for backup of the RAID, unless you like living dangerously.

    If your really serious about performance, but don't want to tempt the Gods, get a RAID card that supports a RAID 5. Then you have better performance and better hardware failure tolerance........
    G4AGP(450)Sawtooth, 2GHz 7447A, 2GB RAM, Raptor/SE16/Firmtek, Radeon 9800 256MB, Mac OS X (10.5.5), ATI Silencer, DVR-116, 23"ACD, Ratoc USB2.0, QCam Ultra, NikonCoolscan, 520W PSU
  • Grant Bennet-Alder Level 8 Level 8 (48,095 points)
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    Oct 3, 2008 6:56 AM (in response to japamac)
    Server gurus love to remind us that mirroring improves UPTIME, but does not eliminate the need for BACKUP. Certain failures, including User Error, can still wipe out data.

    Uptime is improved because a replacement for one failed drive can be added in, and then the mirrored array can be rebuilt in the background. Meanwhile, the mirrored array continues to provide files, but with only one drive.
    Beige G3,G3 B+W,G4/867,G4/MDD, Mac OS 8.6 or Earlier, and 9.2, 10.4 and Server - LW IIg, LW 4/600, ATalk ImageWriter LQ
  • motsteve Level 2 Level 2 (225 points)
    Thanks guys for the info. It helped a lot. I especially appreciate the mention of backup. I use SuperDuper and Tri-BackUp. I've got backup to my backup. Call me paranoid if you like, but I hate standing there looking like a horse's tail end and crying about lost data and irreplaceable applications because I didn't do some simple housekeeping.
    iMac 20" and G4 Digital Audio, Mac OS X (10.5.5), G4 is MacOSX(10.4.11) iMac 3G ram G4 1G ram
  • japamac Level 7 Level 7 (24,390 points)
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    Oct 3, 2008 7:30 AM (in response to motsteve)
    Some more interesting information is had in this article about the virtues of SoftRAID vs. OS X RAID.
    I've got backup to my backup. Call me paranoid if you like, but I hate standing there looking like a horse's tail end and crying about lost data and irreplaceable applications because I didn't do some simple housekeeping.

    Add me to the "tri-backup" team (the wife hates all my hard drives.... sees money spent, I guess....).
    I also keep 'hard copy" DVD of archived data, and all photos and audio. It only takes losing some important data once to underscore the importance of backup. In my case, it was a near miss (was able to scavenge the SCSI drive), but it scared the bejeebers outta' me......
    G4AGP(450)Sawtooth, 2GHz 7447A, 2GB RAM, Raptor/SE16/Firmtek, Radeon 9800 256MB, Mac OS X (10.5.5), ATI Silencer, DVR-116, 23"ACD, Ratoc USB2.0, QCam Ultra, NikonCoolscan, 520W PSU
  • motsteve Level 2 Level 2 (225 points)
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    Oct 3, 2008 7:53 AM (in response to japamac)
    Hard drives are cheap. What about all those video cards?
    iMac 20" and G4 Digital Audio, Mac OS X (10.5.5), G4 is MacOSX(10.4.11) iMac 3G ram G4 1G ram
  • japamac Level 7 Level 7 (24,390 points)
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    Oct 3, 2008 8:37 AM (in response to motsteve)
    Shhhhhh! Video whats ?
    G4AGP(450)Sawtooth, 2GHz 7447A, 2GB RAM, Raptor/SE16/Firmtek, Radeon 9800 256MB, Mac OS X (10.5.5), ATI Silencer, DVR-116, 23"ACD, Ratoc USB2.0, QCam Ultra, NikonCoolscan, 520W PSU
  • Grant Bennet-Alder Level 8 Level 8 (48,095 points)
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    Oct 15, 2008 4:32 PM (in response to rezwits)
    That article japamac cited says booting should also work for Raid 0 (striped), provided you are using 10.3 or later.

    I wanted to add one more note for completeness. Due to protocol restrictions, two IDE/ATA drives sharing the same cable as Master and Slave get no benefit from overlapped I/O. ATA requires the first command to complete (seek, read, transfer_data) before the second command can even begin. For top performance, your mirrored or striped drives should be on separate cables, if you have the hardware to support it. But don't move one to the CD Drive cable, sharing with the CD slows it down much more, because IDE/ATA can only see speed data for the slower drive.

    The Mirrored Drive Doors G4 has an ATA-100 drive cable as well as an ATA-66 drive cable, in addition to its CD-drive cable.
    Beige G3,G3 B+W,G4/867,G4/MDD, Mac OS 8.6 or Earlier, and 9.2, 10.4 and Server - LW IIg, LW 4/600, ATalk ImageWriter LQ

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