Toshiba HGST 3TB Hard Drive (HDKPC08/DT01ACAxx)
Thanks to OWC for making the Toshiba HGST hard drive available for testing.
The Toshiba HGST 3TB hard drive* is a next generation Hitachi hard drive beyond the Hitachi 4TB 7K4000 series (Toshiba acquired Hitachi).
*The drive displays in Disk Utility as “3 TB Hitachi HDS723030BLE640 Media”
The Toshiba HGST 3TB is a 6 gigabit per second (“SATA 6G”) hard drive, backward compatible with 3 Gbps and 1.5 Gbps SATA also. The 6Gbps interface is welcome, and could help improve burst transfers out of the drive’s cache, but on any Mac Pro through 2012, the internal SATA ports are 3G only.
Bigger is faster
Looking for a fast 1TB or 2TB drive?
The Toshiba HGST 3TB sounds little different than the Hitachi 4TB 7K4000.
disktester fill-volume volume-name
The DiskTester fill-volume command writes 1000 files to fill the volume to 99% capacity, then reads those 1000 files back while checking for data errors. The resulting data can be graphed to characterize the performance across the drive, as seen below.
Single drive sustained transfer MB/sec
Sustained transfer speed is the metric most important for most users, and especially for opening large files in Photoshop and similar.
Write performance declines very consistently across the drive as it does with all hard drives; see Larger Hard Drives Are Faster Than Smaller Ones.
This is one fast drive! It runs about 20MB/sec faster than the Hitachi 4TB 7K4000, which is around 12% faster. As hard drives go, that’s a very significant advance in less than a year.
The graph below is an average of two drives, which were nearly identical in performance. Click to view a larger graph.
RAID-0 striping for faster performance
Single drive performance is outstanding (for a single drive) but only to about 2/3 of capacity. Speed then then declines rapidly. Utilizing a two-drive RAID-0 stripe for one’s Master volume bumps up performance greatly.
A 2-drive RAID-0 stripe is the default configuration for the Master volume in an MPG Pro Workstation, precisely for that reason: performance more than doubles— for any given amount of usage, only the faster portion of the drive is used (as compared to a single drive for the same amount) *and* that speed is doubled by the striping using both drives simultaneously).
While doubling the capacity to 6TB is a bonus side-effect, the 2-drive stripe containing 6TB is still more than twice as fast as a single 3TB drive. Two drives striped are enough for a very responsive system for virtually any big-file storage challenge (a fast PCIe SSD is still better for specific I/O intensive uses).
Bottom line here is that a two-drive stripe of the Toshiba HGST averages a whopping 300MB/sec speed across the entire 6TB capacity. That kind of sustained transfer speed is in the range of some SSDs.
The usual hard drive speed dropoff is apparent with one unusual quirk— something in the I/O stack decided to allocate the last 240GB or so onto the fast part of the drives. It is not a cause for concern.
It’s unclear if the OS X file system is responsible, or the drives themselves via some kind of block remapping. To that point, partitioning the drive into 95% / 5% partitions (first 95%, last 5%) shows the expected very slow speed on the 5% partition, so the drive is not doing a remapping (ditto for a RAID-0 partioned test). Hence it seems to be OS X file system behavior, perhaps something new with 10.8.2.