Bests & Worsts Reviews from Amazon

Bottom line: I recommend the TR-004 with drives I mention below (or others on its list of supported drives) in one of the 3 modes: Individual, RAID 1/0, or RAID 5. Please keep in mind that RAID is not a substitute for a good backup. You should always keep a backup copy of anything important on a separate device! If you want to know more details, read on. As an IT professional, I appreciate the benefits of using RAID. It provides faster performance than any one of the drives in the array. How much so depends on the type of array you configure. Configured properly (more on that later*), it provides safety against data loss when a drive fails, and that's always a matter of when, not if. My only complaint with the TR-004 is that the trays that the drives go in are a little flimsy. The down side of RAID is often cost - it's not terribly cheap. Building a home network storage server using it can be expensive because motherboards that support it cost more that those that don't. Using a dedicated controller card is often even more so. I could never convince my better half to let me build a file server with enough storage to meet our needs using RAID because of this - until I found the QNAP TR-004. The TR-004 is a great price when you consider that it has the RAID controller built in. It's an even better value because it supports many of the various popular levels of RAID (more on that later*). Add the fact that you don't have to fill every drive slot to use it, and it's a high value for the money. I put it on a tiny PC also available here on Amazon.com for under $200, and **boom** - instant dedicated file server for home! You need to populate the TR-004 with drives, it comes without any. Get good NAS or other server grade drives. I recommend WD RED, WD PURPLE, or WD GOLD from Western Digital, or Seagate's IronWolf or SkyHawk lines. These drives are specifically designed for use in RAID arrays for Network-Attached Storage, also called NAS (WD RED & IronWolf), security camera systems (WD PURPLE & SkyHawk) or other servers (WD GOLD & IronWolf). They are made for very high reliability. At the very least, use either the Western Digital WD BLACK or high-end Seagate Barracuda drives. Anything cheaper, and you'll end up having problems with your RAID array loosing sync. "What's that mean?" you ask? In simple terms, all the drives in a RAID array look, to the computer, like a single giant drive. Data gets spread across the drives in chunks. This is how you get the speed performance increase from RAID. While one drive is busy handling one thing, others are frequently able to handle other things. It's also how you get protection against data loss if a drive fails, when you are using a level of RAID that provides this. * Here's the "more on that later" I promised above. RAID comes in different "levels", referred to as RAID x, where x is a number. All RAID arrays are made up of multiple drives. The TR-004 supports 6 different modes, though I only recommend 4 of them. These modes are: Individual - Every drive in the TR-004 is visible to the computer as a separate drive letter (ie: e:, f:, etc). The drives can all be different models, brands, and sizes. I can recommend this mode, but know that data on each drive will be lost if that drive fails and the data on it isn't backed up elsewhere. If you are going to use this mode, you can use any drive the TR-004 will support, not just the ones I mentioned above. JOBD - This stands for Just One Big Drive. All the space of all the drives is available to the computer as one giant drive. It requires at least 2 drives, but supports as many as the controller can handle, 4 in the case of this enclosure. This mode allows the use of different, models, brands, and even sizes of drives. It works by spreading the data within files across all the drives in the array (as do all the RAID levels in one way or another). DANGER: If any drive fails, all data on all drives in this mode is lost, unless it's backed up elsewhere. I do not recommend this mode. RAID 0 - This is technically the first RAID mode. It's the same as JOBD, with the notable exception that all the drives in the array should be identical, the same exact model number, the same brand, the same size. The only difference their should be is the drives' serial numbers. This requirement is continued to all the rest of the RAID levels. RAID 0 is fast, however it has the same danger as JOBD, so I do not recommend this mode, either. RAID 1/0 - This mode is also know as RAID 10. It requires an even number of identical drives, and a minimum of 4 (all bays filled in the TR-004). It copies 2 RAID 0 arrays between each other. In larger arrays, an even number of identical drives is required for RAID 1/0. This is the fastest of the RAID levels, but it has the drawback of only making half the total space of all the drives combined to the computer (ie: 4 drives of 3 TB each would look like 6 TB to the computer [4 drives * 3 TB = 12 TB, 12 TB / 2 = 6 TB]). Although I do not recommend RAID 0, the fact that there are 2 identical copies of a RAID 0 array, any single drive can fail without loosing data. Therefore, I do recommend RAID 1/0 for speed and data redundancy. RAID 5 - This mode is a good compromise between between the speed of RAID 1/0 and the desire to get more storage space from the drives in the array. RAID 5 also requires at identical drives. It needs a minimum of 3, but can go up from there to however many drives the controller can support, in single drive increments. It achieves redundancy, by spreading data across "stripes" that are duplicated on the multiple drives. At it's absolute simplest, it places 2 copies of each stripe in the array. For example, lets say there are 3 stripes stored in a 3-drive array. We'll call the stripes A, B, & C. We'll call the drives 1, 2, & 3. RAID 5 stores a copy of A on 1 & 2, a copy of B on 2 & 3, and a copy of C on 3 & 1. By doing this, any 1 drive can fail but there is still at least 1 usable copy of all stripes in the array. Replace the failed drive, and the controller will copy the necessary stripes to the new drive. The amount of storage available to the computer is the combined total of the storage on all but one of drives in the array (ie 4 drives of 3 TB each would look like 9 TB to the computer [4 drives -1 = 3 drives, 3 drives * 3 TB = 9 TB]). RAID 5 is not as fast as RAID1/0, but it gives more storage from the same drives, so I do recommend it in particular for home servers, where cost is a bigger consideration that many businesses. SFOTWARE CONTROL: When the TR-004 is in this mode, special software must be downloaded and installed on the computer it is attached to. The mode it will run in will then be controlled by the user from within this software. I do not recommend this mode because if you are going to move the TR-004 from one computer to another, you may accidentally loose everything stored on it. You never know when you may have to move it to another computer - say if the one it's on dies?