I got a 3rd 1TB hard disk to put in my Raid 0. The files on the array had gotten to be over 1TB large, which meant that I'd not be able to rebuild it immediately if one disk failed. This way I'd be able rebuild the array immediately. I was also hoping that putting a 3rd disk in would speed up the array. I did get the updated Caviar Black disk with a 64MB cache, not the 32MB cache my current two 1TB Caviar Black disks have.
Speeding up the array seems to have worked, with sequential read/write speed a bit over 300MBs now, compared to a bit less than 200MBs with two disks. On a empty array before restoring my data speeds were up around 350MBs.
Now:
Previously with two disks, a few months ago:
The 1000MB vs 4000MB file size differences shouldn't matter much. A bigger deal is that I've not yet rebuilt all the large caches CS5 and Lightroom can create, which will slow down the disk a bit, since disk slow down as they fill up and data is written on the slower parts of the disk. What did surprise me is that, due I assume to an attempt to see if I could push my overclock a bit faster, I broke the Raid array, a failure from which it could be reset, but which made the array's speeds fall below 200 MBs again. Resetting and reformatting the array got me back to the original speeds.
I'm quite happy with the backup software SyncbackSE, which works much better than the Windows 7 backup. First of all, it is much faster, taking about 1 minute to run if there aren't any big changes to files. Backing up 800 GBs takes a bit over 4 hours, restoring it (for some reason) 9 hours. Windows 7 takes about a day to back up and I've never dared restore from it (though I have rewritten the boot disk once, when I was switching the SSD boot disk controller). So I'm backing up only using SyncbackSE now for most files, except for having Windows 7 back up the system disk. Still, given justified paranoia, there are two backup disks, since I don't want to run the danger of a failing backup disk just when you need it. Which leaves the mystery of how Microsoft manages to deliver horrible backup software...how hard can it be?
I also got a fan for the bottom drive bay. So I have 1 128 GB SSD, one 3 * 1TB Raid 0, 2 * 2 GB backup disks (one internal and one external), one 500 GB scratch disk (a leftover from my previous machine), for a total of 7,628 GB of hard disk space. Six fans, all pretty quite except for one exhaust fan..I should probably try to figure out how to turn down the exhaust fan, but having it turned up does keep temperatures down.
One negative aspect of all this is that my old machine, passed down to kid #1, now seems intolerably slow. It also makes a lot more noise, both the disk drives and the fan. I'm not sure I can do much about the fans, but I may be able to the oldest hard drive, if it is the loudest one, and instead back up onto an external drive.
Counting down to disk failure now...
Update #1: yes, several more failures, with the new disk dropping out of the array. It's going back to Amazon for a refund.
Turns out this is a known issue with the WD 1002FAEX, the newer 64MB cache version of the 1TB Caviar Black:
Note that WD still - erroneously - state that the WD1002FAEX is tested and recommended for desktop/consumer RAID environments, such as Intel Matrix RAID. Go with this advice, and you'll be sorry, though - WD removed the TLER switching functionality that prevented drives dropping out of RAID volumes.
My older 1TB 32MB cache WD1001FALS Caviar Blacks still have TLER (or at least they don't drop out of the array -- I would need to track down the TLER management tool to check). TLER is
Time-Limited Error Recovery (TLER) is a name used by Western Digital for a hard drive feature that allows improved error handling in a RAID environment. In some cases, there is a conflict as to whether error handling should be undertaken by the hard drive or by the RAID controller, which leads to drives being marked as unusable and significant performance degradation, when this could otherwise have been avoided.
More here.
Obviously, this could just be a bad disk, and FAEX doesn't need TLER to run in a Raid 0 -- which is what I was hoping for (and which is what the WD product spec web page suggests).
Note that charging $89 for the FAEX without TLER and $140 for the RE4 version with TLER is an example of price discrimination. The RE4 may have somewhat better testing and better specs, but it appears to be essentially the same HDD. I suspect they come off the assembly line, get tested, and the ones with better test results get TLER and become RE4s, the rest that pass inspection don't get TLER and become FAEXs.
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