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Introduction
When surveying the various storage upgrade options available for my G4 something was appealing with setting up a SCSI RAID. Maybe it was my fond memories of setting up a SCSI RAID using a Jackhammer in my old 7500 but for what ever the reason I was drawn to the idea of my G4 spinning on SCSI. Firewire800, SATA or new fast ATA drives could have worked but with U-320 drives under $150 the joy of high powered SCSI can be obtained for almost the same amount of money.
Equipment
I purchased two Maxtor Atlas 10K IV 8B036L0 36.7GB 68pin U320-SCSI 10,000RPM Hard Drives from ZipZoomFly for $145 each. I then picked up two U-320 rated Amphenol Spectra-Strip cables from B & A Computer (
http://www.stores.ebay.com/bandacomputercablesandmore) that come with a cheap looking terminator marked U-320. Since LVD drives are not able to terminate themselves, an external terminator is required. The nice price allowed me to get two cables so that each drive could be on its own channel. The cables and terminators were $60. (NOTE: Everyone claims the benefits of using Granite Digital cables and terminators. Granite Digital cables are very high quality but at close to $200 for two cables and terminators they were not an option in my budget.) I am using an Adaptec 39610 Dell OEM model that I purchased on Ebay for $85. The 39610 was flashed via 9.2 and is using Adaptec's latest firmware (v1.2).
- OS 10.2.8 and 9.2.1
- Power Mac G4 (Quicksilver) at 867 MHz
- Adaptec 39160, firmware 1.20
- Two 36.7GB Maxtor Atlas 10K IV hard drives
- Two U-320 rated Amphenol Spectra-Strip cables and U-320 terminators
- One 9.5ä Power Supply Extension Cable
The Adaptec 39160 with firmware 1.20 is bootable from OS X when using the Open Firmware hack that is posted on Adaptec's website. (Note: he's referring to the nvram patch/tweak mentioned here previously on the G5 compat. page/PCI cards section, which Adaptec notes is needed for 29/39160 card used in Quicksilver and later Macs to allow booting from connected drives. I also added the info to the FAQ's Controllers/PCI SCSI cards section back then.-Mike) The 39160 also requires the latest OS X drivers from the Adaptec website. I have yet to test the card and drivers under Panther. RAID 0 support is provided via Apple Disk Utility.
Installation
The Atlas 10K IV's install nicely into the two single drive brackets next to the dual IDE drive bracket. I also had to attach a power supply extension cable. The cables and terminators fit snuggly but do not seem to create any cooling issues. Initially I had some problems seeing the drives in OS X. After several attempts with the jumpers I got everything working. I left all of the jumpers off except for one to create the SCSI ID 1. The other drive without any jumpers is set to SCSI 0.
Temperature and Noise
The drives sound almost twice as loud as the stock Seagate ATA. The Quicksilver is loud to begin with but I have replaced the fans with Pabst/Panaflo and can normally hear my ATA drives just slightly. These Maxtor drives in a stripe are clearly audible albeit it a pleasant SCSI chirp. Sound is very objective but I would claim that these drives are tolerable for desktop use. The drives do get warm but I have noticed very minimal temperature increases on my CPU heatsink probe.
Configuration and Performance Tests
Using xbench I tested my onboard ATA drive, one of the Atlas drives, followed by a RAID 0 test. I have since been booting off of the RAID 0 disk with OS X 10.2.8 without any problems. I also have yet to see any sleep related problems.
System Info
Xbench Version 1.1.3
System Version 10.2.8 (6R73)
Physical RAM 1024 MB
Model PowerMac3,5
Processor PowerPC G4 @ 867 MHz
Version 7450 (V'ger) v2.1
L1 Cache 32K (instruction), 32K (data)
L2 Cache 256K @ 867 MHz
L3 Cache 2048K @ 217 MHz
Bus Frequency 134 MHz
Video Card GeForce2 MX
1 60GB ATA, Onboard - ST360021A
Disk Test 69.99
Sequential 65.35
Uncached Write 57.76 24.08 MB/sec [4K blocks]
Uncached Write 57.05 23.36 MB/sec [256K blocks]
Uncached Read 106.46 16.85 MB/sec [4K blocks]
Uncached Read 58.92 23.81 MB/sec [256K blocks]
Random 75.33
Uncached Write 79.38 1.19 MB/sec [4K blocks]
Uncached Write 65.84 14.85 MB/sec [256K blocks]
Uncached Read 87.83 0.58 MB/sec [4K blocks]
Uncached Read 71.81 14.78 MB/sec [256K blocks]
1 Atlas 10K IV - ATLAS10K4_36WLS
Disk Test 126.74
Sequential 139.32
Uncached Write 112.01 46.69 MB/sec [4K blocks]
Uncached Write 162.25 66.44 MB/sec [256K blocks]
Uncached Read 129.42 20.49 MB/sec [4K blocks]
Uncached Read 169.70 68.56 MB/sec [256K blocks]
Random 116.24
Uncached Write 94.39 1.42 MB/sec [4K blocks]
Uncached Write 138.73 31.29 MB/sec [256K blocks]
Uncached Read 134.20 0.89 MB/sec [4K blocks]
Uncached Read 109.19 22.47 MB/sec [256K blocks]
2 Atlas 10K IV RAID x 2 Channels - ATLAS10K4_36WLS
Disk Test 169.38
Sequential 169.37
Uncached Write 122.37 51.01 MB/sec [4K blocks]
Uncached Write 274.36 112.35 MB/sec [256K blocks]
Uncached Read 114.36 18.10 MB/sec [4K blocks]
Uncached Read 327.26 132.23 MB/sec [256K blocks]
Random 169.39
Uncached Write 172.24 2.58 MB/sec [4K blocks]
Uncached Write 191.10 43.10 MB/sec [256K blocks]
Uncached Read 151.03 1.00 MB/sec [4K blocks]
Uncached Read 167.97 34.57 MB/sec [256K blocks]
(Real-world tests are also welcome and preferred over Xbench/Pure benchmarks. For example Duplicating large files or a folder with many files from the target drive. TAD later sent results of those tests:)
Here are the times for file tests:
- One 60GB ATA, Onboard IDE - ST360021A
Large File Test (853.2MB file size) - 76.8 seconds
1000 File Folder (4k file size - 4MB total) - 2.2 seconds
- Two Atlas 10K IV RAID x 2 Channels - ATLAS10K4_36WLS
Large File Test (853.2MB file size) - 26 seconds
1000 File Folder (4k file size - 4MB total) - 4.4 seconds
I was kind of surprised to see the drop off with the 1000 file folder...
(he later sent more tests)
Mike, Here is another file folder test result on a larger folder:
Duplicate OS9 System Folder (375.4MB folder size)
- One 60GB ATA, Onboard - ST360021A - 58.1 seconds
- Two Atlas 10K IV RAID x 2 Channels - 38.6 seconds
The SCSI factor is now evident.
Conclusion
Although I am sure that this configuration could be made faster with better cables and terminators, what is evident is that these drives are very quick in RAID 0. For under $500 I was able to build a very fast boot drive that appears to make the entire computer feel a little faster. Applications are snappier and everything seems to run smoother.
There is something comforting in running a "striped" array using SCSI. (RAID 0 Stripe is the least reliable RAID mode since if one drive fails, the entire volume is gone. RAID 1 mirror is slower but is redundant) OS X seems to love it and it feels solid in everyday use. While there is some extra hassle and cost, SCSI still has an important place on the desktop.
-TAD
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