Western Digital 80GB (WD800JB) Hard Drive in RAID Review
Western Digital have propelled themselves to the forefront of Hard Drive technology. Last month on June 25th they confirmed their position at the top by announcing its WD Caviar 200 GB 7,200 RPM product featuring amazing densities of 60GB per platter.
They are also the first to introduce groundbreaking technologies in the lower echelons of their products in terms of sheer capacity. The WD800JB Hard Drives offered something that nobody else had produced, a product with 8MB cache as opposed to the normal 2MB cache on their Caviar series of drives. No wonder they dubbed it special edition.
The special edition WD800JB drives come in 3 capacities, 80, 100 and 120GB featuring 40GB per platter. With this cache Western Digital claim to have the fastest IDE drives around.
We decided to get hold of two of these drives and test them in a configuration that many people are using these days to get maximum performance out of their storage facilities, RAID-0.
RAID, meaning Redundant Array of Inexpensive Disks (although there are many interpretations around Redundant Array of Independent disks being one) was a concept developed initially to improve performance and safeguard mission-critical applications through what is known as striping and mirroring.
There are numerous configurations of RAID featuring different degrees of performance and backup. Most end user motherboards now have on-board RAID controllers but only make use of RAID 0 and 0+1.
RAID-0 implements a striped disk array, the data is broken down into blocks and each block is written to a separate disk drive. As each IDE channel traditionally can read OR write at any one time, spreading information over a RAID array theoretically allows improved I/O performance.
RAID 0+1 usually has 2 drives as shown above in a stripe array but also has 2 other drives mirroring the information on the stripe. This is needed because if 1 drive in the stripe corrupts then all the data on the array is lost. Mirroring these drives is the best way to combine the performance of the stripe array with the piece of mind that if something goes wrong the data is safe.
Advantages of RAID 0
Disadvantages of RAID 0
There is usually little reason for end users to need or fully utilise RAID functions but as with most things in the computer industry these days, it's not what people need it's what people want that matters; people want the best Hard Drive performance available without going down the expensive route of SCSI, they get IDE RAID.
Let's take a look at the drive in more detail...
Western Digital make a special point to note that their Caviar drives have excellent shock tolerance. As shown in the specifications above the WD800JB can handle 65G for 2ms which is almost the equivalent of throwing it against a wall whilst it is in operation. It is nice to have this kind of protection element but I would not recommend you try this out!
Isn't ATA133 the fastest?
True, these Special Edition drives come with an ATA100 interface allowing a theoretical maximum throughput of 100MB/s but of course as many people know, this is never ever achieved, in fact no drive really gets close.
Maxtor are currently the only manufacturer offering ATA133 functionality on their drives, but it seems other manufacturers are keenly anticipating the next generation of storage interfaces; the primary one of course being serial-ATA (take a look at the specifications here).
VIA 4.41 4in1 drivers were used in conjunction with Windows XP.
HDTach is a physical performance hard drive test for Windows 95/98/ME and Windows NT/2000. It displays the results in graph form after testing all areas of the hard drive giving an overall impression of hard drive speed (i.e. the average of outside tracks to inside tracks).
In a single drive configuration it is good to get an impression of what the RAID array can achieve.
Single WD800JB Drive
A maximum throughput of 48.15MBs (49306/1024) shows the drive is rapid to say the least competing with some of the mid-range SCSI drives currently available (Quantum Atlas II 10K rpm springs to mind as an example).
WD800JB in RAID-0 configuration
A maximum throughput of 61.67MB/s (63155/1024) clearly shows how fast these drives are in RAID-0. The HDTach results also show that the performance of the RAID array is not double that of the single drive, it would be fairer to say there is more like a third increase in throughput performance although average speed over the drive is far less that, offering only a 7MB/s increase over the single drive.
As explained on page 1 the CPU load increases drastically when using RAID but in reality, with the systems many people have today this hardly makes much of a difference.
A quick scout through the Madonion ORB suggests this is a decent score but I would tend to go with HDTach as it actually puts some quantifiable numbers into the results rather than "1206".
Sisoft Sandra 2002 SP1
The SiSoft filesystem benchmark reports a much lower throughput than HDTach, probably due to the differing methods the two programs use to establish hard drive performance. HDTach calculates performance over the entire drive whilst Sisoft (like most programs) creates a file of specific size and conducts read/write tests on that file.
Again I would go with HDTach for the results but it's interesting to see how other programs gauge hard drive performance. All synthetic of course and down to individual interpretation.
Fundamentally, these Hard Drives individually are rapid, yet in RAID-0 they are even more so. Despite the theoretical 2x single drive performance turning out to be false the gain in performance is certainly worthwhile if you are in need of the applications RAID is recommended for.
You can buy 160GB Drives now from the leading manufacturers, and whilst the storage is there, the performance RAID can offer to those who need it is not. 160GB drives are close to what I like to call the technology boundary, prices rise exponentially as you get closer to this boundary. A 160GB drive will set you back £200 or more yet 2 of these 80GB special edition Caviars will cost you £180 or so. All that is needed is a motherboard with a RAID controller or of course a 3rd party addon PCI controller card.
A 160GB SCSI hard drive + controller will set you back even more, enhancing the viability of IDE RAID as an inexpensive solution coupled with great performance.
The only downside I could have with the Caviars is that whilst they are quiet, they do generate a fair bit of heat. In the test case the hard drives are quite close together and that whole area is much warmer than I would like. A cooling fan is certainly needed should the hard drives lives not be cut short.
So how to sum up the 2 drives in RAID-0?
I will be picking some of these drives up myself no doubt. Despite the price of hard drives being so low right now the additional gain in performance RAID offers, whilst not immediately needed I may as well make use of.
Copyright © 2002