Once upon a time in the land of IT administrivia, storage was a precious commodity that had to be closely guarded for fears of exceeding available capacity. Then came the days of huge, cheap disk drives, and the guardians of IT administrivia no longer had to worry about running out of space. Then, the Big Data hoarders came along. Now, it seems they are able to fill any and all storage in the blink of an eye.
In reality, there is a real need for simple solutions to adding storage capacity without breaking the bank. The Addonics RAID Tower XIII hopes to fill that need with up to 20 3.5" drive bays presented as four individual storage devices over either an eSATA or USB 3.0 interface. All RAID configuration is controlled via rear-panel dip switches without the need for any software setup. Ample power and cooling fans keep drives cool and steady without sounding like a jet engine. Addonics also sells a network-attached storage (NAS) adapter, although it was not tested in this review.
Installing the Addonics RAID Tower XIII
Addonics groups up to five drives together on each shelf and presents the storage via rear-panel connectors. Installing drives consists of opening a drive door, sliding the disk into a slot and closing the drive door. I did have a little problem getting one of the doors to close, and once the drive was inserted, it was difficult to remove. The drive doors are made out of plastic and aren't meant to take much force. This wasn't an issue on any of the other bays. There are four dual-interface ports on the rear of the case, but, unfortunately, they aren't labeled.
For testing purposes I used four Seagate 2-TB drives (ST2000DL03 5900RPM 6GB/s SATA). Configuring the shelf for RAID-5 consists of setting a single dip switch and then depressing a button using a ballpoint pen while turning on the power. The box recognizes this as an initialization command and commences to configure the drives for RAID-5. Total time to get the drives ready to connect was less than five minutes.
The nice thing about using USB 3.0 is the ability to connect and disconnect while the system is running. USB 3.0 cabling is also a little more flexible and does support longer lengths than eSATA. That would make this box pretty handy for performing hot backups, should you need such a thing. After plugging the USB 3.0 cable into a machine running Ubuntu Server 11.10, I was able to view the drives using the Disk Utility tool. From here, I formatted the array and then performed a mount command.
Measuring the performance of a disk system involves many moving parts. Multiple factors must be considered, from the interface to the raw disk drives to the benchmarking software. For the purposes of this review, I used the benchmark tool from the Ubuntu Disk Utility application. It will measure read-only or read and write. For the host platform, I used a test server based on an ASUS M4A89GTD Pro motherboard and an AMD six-core X6 1090T CPU. The motherboard has both USB 3.0 and eSATA ports available on the rear panel and a USB 3.0 port on the front while providing support for 6Gb/s SATA drives.
To get a true understanding of what performance is actually possible, you must look at all the interfaces. The ASUS M4A89GTD PRO external eSATA port is rated at 3Gb/s. USB 3.0 devices offer a 5Gb/s signaling rate. You must also make sure you understand the terms defining how these speeds are measured. When you see the term 6Gb/s for SATA and 5Gb/s for USB 3.0, it actually means six or five gigabits per second. Most hard drives are measured in bytes or eight bits. To get the maximum possible speed in terms of megabytes (MB) you must divide by eight. That gives us approximately 750 MB/s for SATA and 625 MB/s for USB 3.0. The bottom line for this review comes down to the interfaces on the test server and the fact that the eSATA port is slower than the USB 3.0 port.
This seems to be reflected accurately when you look at the actual benchmark graphs. The USB 3.0 numbers are higher than eSATA but not by a large margin. Many other factors contribute to overall performance, and this simple test was intended to determine if there were any significant speed differences between the two interfaces. Based on the numbers, the answer is, not enough to choose one over the other, strictly based on speed.
Typical use cases for this box would be in a departmental or remote office environment where the server provided easily accessible eSATA or USB 3.0 ports. Adding the Addonics RAID Tower XIII in these scenarios takes literally minutes. The simplified configuration is another big plus when deploying to remote locations where IT support could be limited. Prices start at $965 for a model with four Snap-In Disk Arrays and no drives.