There are two products in the MediaVault range: the 4105, a tower unit with a single PSU, two-port 4Gbit/sec Fibre Channel interface and five parallel-ATA drives; and the 10-disk 4210, which is effectively two 4105s in a single box, which operate independently except for the shared pair of hot-plug, redundant power supplies. The internal drives (all in easy-swap trays accessible via the pull-off front panel) can be 160, 250 or 400GB units.
Both MediaVault offerings have both RAID 0 (striping) and RAID 3 (striping with one disk used to hold error-checking data) capabilities. Most of the storage arrays we've come across have a little configuration application that you use to set up your choice of partitioning and RAID on the unit. Not so with this one there's a little switch on the back of the unit (or each half of a 4210) that lets you switch it between its six standard modes. There are three basic modes: RAID 0, RAID "[email protected]" (RAID 3 with a 2,048-byte block size) and RAID "[email protected]" (as before, but with a 512-byte block). Each mode can be used with or without "Turbo" mode (which uses the highest-throughput portions of the disk first presumably the bits near the edge), thus giving a maximum of six alternatives. To change mode, you turn the device off, select the mode, hold in the "Mode change" button, and restart but beware, as any data on the disks won't survive the experience of a mode change. The lights on the front panel tell you the speed of each FC link and whether you're using RAID3, as well as showing disk activity.
Once you've configured the array as you'd like it, the volume(s) you've defined are then visible to the host operating system and you can format them appropriately with the host OS's own disk setup tools. The documentation says to run Apple Disk Utility, but of course before you get the chance to do so, MacOS spots the unformatted disk and runs ADU for you. As with other arrays such as Apple's Xserve RAID, the two independent sub-arrays in the 4210 can be further RAIDed using software RAID in the host OS or a RAID adaptor in the host server.
The MediaVault, although nothing like as aesthetically sexy as, say, an Xserve RAID, is a cracking little box with the characteristics and speed of a big box. It took us less than ten minutes to get going from scratch for a storage array with 4Gbit/sec interfaces and a capacity of four terabytes in its fully-specced form.
1Gbit/sec or higher Fibre Channel adaptor in host system
Mac OS 9.2 or higher (includes OS X), Windows 95 or later, SGI IRIX, Linux, Solaris
If you're implementing multi-level RAID (e.g. with RAID at the host mirroring over two channels of a 4210) make sure you use a hardware adaptor, as software RAID, though often good, is never as fast as a hardware-based product.