| Nov 13, 2007 |
Introduction
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Last week, we looked at the latest 1TB harddrives from Hitachi, comparing its performance both in single disk configurations and in a 2TB Raid 0 array to the 500GB drives we tested last year. Not to be outdone by Hitachi, Seagate recently joined the terabye club with the introduction of their own Barracuda 7200.11 1TB drives. Like the Hitachi drives we reviewed last week, these new high capacity storage devices are built from the ground up using the recently introduced perpendicular magnetic recording technology. This new technology, which is responsible for the latest innovations in hard drive space possibilities, was first introduced in Seagate's 750GB drives. With this kind of pedegree under Seagate's belt, we expect big things from this, their latest 1TB model. Today, we will be putting Seagate's latest 1TB drives through their paces, both as single drive solutions and in the full 2 terabyte glory that only a striped RAID 0 array can provide. But before we get down to business, lets review some hard drive basics. |
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SATA
SATA is the successor to our old friend, the parallel ATA. There have been numerous iterations of the ATA interface, with varying data transfer rates and storage capacity limits. In stark contrast to the bulky IDE cables of old, the new SATA interface uses low-profile cables that can be easily routed with any other cable in your case. Aesthetics aside, the SATA interface offers significantly improved performance. The serial configuration also allows for much longer drive cables, eliminating the need for sluggish USB and Firewire external drive interfaces. We can now connect directly to the motherboard (using the new e-SATA) and take full advantage of the transfer speed offered by this standard. Not only has the data cable changed, but the power cables have also changed to a 15-pin style that looks much nicer than that clumsy molex 4-pin connector.
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"SATA Strikes Back" (aka SATA2)
SATA has two current standards, known as SATA1 and SATA2. SATA1 is the first generation and has a practical data transfer rate of 1.2 GB/s and a theoretical limit of 1.5 GB/s. SATA2 is the second generation that can support the first generation, but also moves data at about 3 GB/s. This increase is incredible compared to the ATA/IDE rate of 80 MB/s! There are plans for a SATA standard that would run at up to 6 GB/s, but I hear there are practical problems with moving data this fast. For now, I'm quite happy with 3 GB/s. |
RAID
RAID stands for Redundant Array of Independent (and sometimes inexpensive) Disks and there are many configurations and benefits to this setup. RAID systems are often used to cause the operating system to recognize many individual disks as one unit and it's best (often necessary) to use identical drives. In its simplest forms, we have RAID 0 and RAID 1, also known as Striped and Mirrored, respectively. RAID 0 is what I used to configure these drives for our testing purposes. Striping splits the data among the two disks so that the overall data throughput is doubled because each drive takes half of the job of writing and reading data. Mirroring, on the other hand, is used when you absolutely cannot afford to lose your data. The increased data integrity is due to the fact that each drive contains an identical copy of the data, which can be accessed independently in case one drive fails. You can think about Mirroring as setting up an immediate backup, with changes made to both discs simultaneously. To take full advantage of these lovely SATA drives, I have decided to configure and test them in a RAID 0 configuration. Since I recognize that not everybody can buy such large drives in pairs, I'm also testing each of the drives individually. |
