Maxtor MaxLine Pro 500GB drives in 2-way stripe
My storage needs have hit 500GB, which means that one of my backup systems was due for an upgrade in capacity. I purchased two Maxtor MaxLine Pro7H500F0 500GB bare drives at zipzoomfly.com ($239.99 each), and installed them into a FirmTek SeriTek/2EN2 (an exceptionally well-built 2-drive external SATA enclosure).
Next, I created a striped RAID volume with the two new drives, using Mac OS X Disk Utility.
2-way striped RAID volume
It is always wise to run the DiskTester test-reliability command (“disktester test-reliability BackupDuo”) overnight on new volumes that are to be put into production—which I did. No errors were detected.
The new volume was then tested for performance on the Macbook Pro using the FirmTek SeriTek/2SM2-E ExpressCard 34 adapter, which provides two external SATA II ports. I also performed the identical test on the PowerMac G5 Quad (using the Sonnet Tempo E4P PCI Express card).
The results are quite good, though they are about 25% slower for writes than the 300GB Maxtor 7v300F0 (see Feb 16 blog entry). But they are in a different enclosure, and tested with an updated system, so this is not a surety.
Observe how performance drops on the outer tracks of the drives; speed is only about 60% of maximum as data is read from the outer tracks. This is true whether you use a single drive or a striped RAID. But at least with a striped RAID (in which the hard drives work in parallel to store alternating chunks of data), worst-case performance still remains well above that of the maximum performance of a single drive. When backing up 500GB of data, a 4-way stripe can accomplish the task in about 90 minutes; on a single drive that jumps to about 6 hours—long enough to discourage regular backups.
MacBook Pro DiskTester Results
“disktester run-area-test --iterations 3 --chunk-size 32M --test-size 2G BackupDuo”
---------- Averages for "BackupDuo" (2GB/32MB, 3 iterations) --------- Area (928.8GB) Write MB/sec Read MB/sec 0% 122.3 132.4 10% 127.3 131.9 20% 128.3 131.0 30% 126.4 126.8 40% 125.2 124.1 50% 122.0 120.9 60% 114.4 113.4 70% 109.2 107.2 80% 100.1 98.5 90% 89.2 87.8 100% 75.2 74.6 Average write speed across the volume: 113MB/sec Average read speed across the volume: 114MB/sec Command "run-area-test" executed in 1238.39 seconds.
PowerMac G5 Quad DiskTester Results
“disktester run-area-test --iterations 3 --chunk-size 32M --test-size 2G BackupDuo”
--------------- Averages for "BackupDuo" (2GB/32MB, 3 iterations) -------------- Area (928.8GB) Write MB/sec Read MB/sec 0% 122.3 133.9 10% 126.5 133.7 20% 128.7 131.1 30% 126.7 126.6 40% 125.6 124.5 50% 121.9 121.7 60% 114.0 114.0 70% 108.9 108.0 80% 99.7 99.0 90% 89.0 88.3 100% 75.2 74.9 Average write speed across the volume: 113MB/sec Average read speed across the volume: 114MB/sec Command "run-area-test" executed in 1236.13 seconds.
