Setting up a RAID of system drives

Question

hello everyone,
I am looking to add a second system drive for more hd space. I was planning on purchasing a second Raptor and setting up a RAID 0. will I need to format my existing drive, or can I just plug in the new drive and set up my RAID in DU?
...any feedback appreciated, thanks.
Dual-core PwrPC 2.0ghz G5 2mb RAM Mac OS X (10.4.6)

Answer 1

Ok,
You already have a Raptor as boot, most likely it's a 36 or 74GB with 8 MB cache and it's hooked up to your internal SATA ports.
To create a RAID O, you must match the two drives exactly. Erase w/Zero both of them, create the RAID O set in Disk utility and clone your boot drive back from a booted external drive using cloning software. (meaning you have to first clone the original to a external then boot from it and clone to the RAID O)
Problem: Western Digital has updated all their drives with a new SATA spec, also increased the cache to 16 MB. The PowerMac's can't handle the new SATA spec (supposedly the Quad can, but I'm hearing mixed stories)
So unless you find a 8MB cache Raptor, your going to need to spend more money.
The solution if your determined to have RAID O Raptors, is to buy two of them, preferably the new 10,000 RPM 16MB cache 150GB ones, and a Firmteck SATA PCI card (the only one that's bootable off of) with 4 internal SATA ports and 4 external ports. Then hook the internal Raptors to that.
The Firmteck card will also give you the option of hooking up external SATA drives in a powered enclosure, one cable to each drive. So you can expand if you wish.
With a RAID O, you must clone (for a whole boot drive) or backup (for files) quite regularly, like at least once a week for clone and daily backup for files. Since one should be doing this anyway, it's really no big deal. Because like the other poster said, RAID O is a bit more risky, one drive goes you lose all data as the data path is split. But the speed is worth it. So with a pair of 150GB Raptors your going to need a 250-300GB drive external Firewire 800/400 drive.
Now to keep a drives performance up, you shouldn't fill it more than 50%, and certainly shouldn't fill a boot drive more than 80%. So one can use a 250GB external drive for clone backup as long as the data on the 300GB RAID O doesn't go over around 240GB. (80%) Get it?
LaCie makes a good Firewire 800/400/USB d2 drive.
However if this is a bit too much to bear on your wallet, then what you can do is reduce what you have on the boot Raptor below 50% by moving just what you have in documents, pictures, movies and audio files into NEW folders on a second internal SATA drive (preferably one with 16MB cache not from Western Digital)
Once you have slimmed up your Raptor, then clone the whole drive to a external drive, option boot from it and make sure everything works correctly, repair permissions and test all software (some copy protected ones will need to be fixed). Once your are 100% certain it's ok, then Erase w/Zero the Raptor and clone the whole drive back.
What this will do is optimize the Raptor boot drive drive, free up disk space, de-fragment large files/apps and sort of tighten everything up to the most fastest part of your boot drive, the outer tracks, in the good part of the 50% side of your drive. (vs the inner tracks where performance starts to suffer)
Without the space hogging files that are now on the second SATA drive, your drive freshly optimized, the arm in the hard drive has less space to travel to get your data that Mac OS X, apps and random music files iTunes needs to constantly access.
Now I suggest using Carbon Copy Cloner to do your optimizations with, because I know how this program clones drives, in alphabetical order on the main directory of your boot drive. So Applications, Developer (if you have installed Developers Tools from Tiger install disk) Library, System and finally Users at the end (where it could expand without de-optimizing your drive)
Always follow these rules when cloning.
1: Don't run or do anything else while a cloning process is going on.
2: Always Disk utility Erase w/Zero option all new drives one time or in the case of a security issue.
3: Option boot from the clone and check it out.
4: Repair permissions BEFORE and AFTER each cloning.
5: Avoid partial clones because of copy protection schemes hiding files on the drive.
6: Avoid cloning to partitions, especially on the same drive, because if the drive fails mechanically your screwed out of your clone as well. Keep it a boot clone to a boot clone on a separate drive.
7: If you can keep two clones of your boot drive, just in case you get hacked or have a exploit, because when you hook up the second clone, it will get owned too and possibly erased. If this happens, C boot off the installer disk (write protected) and Erase w/Zero all infected drives and disconnect from the internet/network before hooking up that last clone.
I wrote a book, I hope it helps.
Note to others: Firmteck SATA PCI card will not work in PCI-Expressed based PowerMac's.
http://www.amug.org/amug-web/html/amug/reviews/articles/firmtek/1eve4/