For my TGB buds, I am reposting the following from the AVSForum's Sony XL3 thread. It really could go in the XP MCE thread as well, not so much applicable in Win7. Here's the deal: I bought two of those nifty new 2TB drives, thinking I would use them to replace my 2x1TB RAID0 Recorded TV drive, and have had nothing but frustration, primarily because the XL3's Intel RAID software won't allow a RAID bigger than 2TB, and Vista Home doesn't support dynamic disks, which are a prerequisite to software RAID within Windows. Apparently all versions of Win7 do (so I'm told), so the below solution isn't as useful for Win7 owners, but it still would work. I also considered moving the RAID to an external USB or eSATA enclosure, but they're not really ready for 2TB drives yet, either, until you get to the really pricey ones or WHS boxes. The below works, is simple, and cheap, cheap, cheap.

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Who needs RAID? I'm running JFSA!

I hereby announce a new and revolutionary kind of computer storage volume: the JFSA (Jeff's Forced Switching Array) (my girlfriend's idea).

1. I set up each of my two 2TB drives with a Recorded TV folder.
2. I named the drives T and V (get it?).
3. The Recorded TV folders on both drives are set up as Watched Folders ("More TV locations")
4. I went into VMC setup and pointed recorded TV to T, maximum capacity.
5. I opened up RegEdit, navigated to hkey local machine, software, microsoft, windows, current version, media center, service, recording. I right-clicked on the key name and Exported it as C:\T.reg.
6. I closed regedit.
7. In VMC setup, I pointed recorded TV to V, maximum capacity.
8. I opened regedit, which is still displaying the previous path, and Exported the key to C:\V.reg.
9. I wrote the following in Notepad and saved it as C:\JFSA.wbt (WinBatch extension):

t = diskfree("t")
v = diskfree("v")
if t < v then goto vbigger
run ("regedit", "/s c:\t.reg")
exit
:vbigger
run ("regedit", "/s c:\v.reg")
exit

10. I then set C:\JFSA.wbt to run as a scheduled task at 4AM every day. It's been years since I used Task Scheduler, that was actually the most difficult part of the whole thing, to figure out its new and much more complicated interface (it took me ten minutes just to find it in Administrative Tools - Vista Task Scheduler is 100 times more complicated that I needed for this job).

T and V are set equal the free space of the two drives. If T is less than V, then V has more space available, so the program jumps to vbigger, which merges v.reg with the registry and points Recorded TV to the V drive if it wasn't already. Otherwise, the T drive must have more space (or be the same size, pretty much a miracle) and t.reg is merged, pointing Recorded TV to the T drive.

In essence, this will regularly arbitrate which drive the XL3 records to, always striving to balance the total usage of both. Very much like a RAID0 span, without the added speed but also without the risk of losing all data if one drive fails (because the files aren't actually spanned or linked at all, each file exists entirely on one and only one drive), and without needing a RAID controller, or RAID software, or even a specific version of Windows, for that matter. What makes this gimmick work is that since both drives are Watched Folders, all my shows appear within VMC regardless of which drive happens to be the target at the moment.

I should point out that JFSA is not limited to two drives or even ten - you could have as many drives as you can have letters assigned to. JFSA doesn't even care if they're all the same size, because it's the remaining space that's considered, not the capacity. For more than two drives, I'd change the program to use other WinBatch commands that identify the largest of a matrix of variables rather than a simple "<" two-factor comparison, although it could be done using a cascade of sequential greater than or less than commands, too. For just two drives, I suspect you don't really even need WinBatch - this could probably be done by a clever DOS batch file or any programming language except maybe GW-BASIC.

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One last note: in prior posts in the XL3 thread, I reported my experiments regarding changing recorded TV paths in the middle of recording a show. Turns out that MCE, at least in Vista (I run TV Pack, so YMMV) is smart enough to complete an ongoing recording before switching drives, so I don't have to check if a show is actively recording or if Live TV is buffering before switching the folder path. I have confirmed that JFSA works by deliberately pointing VMC to the drive with the lesser free space and then verifying the next day that VMC now pointed to the drive with more space, but I can't really say it's fully validated until the time comes that JFSA switches drives in the middle of a recording.  I'm also considering adding in some simple error checking, such as triggering a popoup message and exiting if the T or V drives aren't found.

Here's the final JFSA file. It contains one more registry snippet, for which I set the VMC Recorded TV path back to the default C: drive, set the usable space to the next number under maximum (because running out of space on C: can wreak havoc), and exported the key to C:\Windows\C.reg. I've validated the below under a number of scenarios, including having a show recording while the JFSA task came up as a scheduled task, and then recording another show afterwards, and verifying that the drive changed, the second show recorded on a different drive, and both shows recorded okay. I've also checked that both shows record when they are on the same channel or different channels, and with Media Center running and with Media Center closed.  I've also thoroughly verified the error checking by changing the drive letters for disks T and V and confirming that JFSA pops up the expected error message. In short, I consider this validated - and extremely useful.

If DirExist("T:/Recorded TV") then Goto TExists
If DirExist("V:/Recorded TV") then Goto VOnly
Pause("FATAL DRIVE ERROR","No TV drives found.%@CR%Click OK to set%@CR%Recording Path to C:")
Run ("regedit", "/s c:\windows\c.reg")
Exit
:VOnly
Run ("regedit", "/s c:\windows\v.reg")
Message("CRITICAL DRIVE ERROR","T Drive not available.%@CR%Recording Path set to V:")
Exit
:TExists
If DirExist("V:/Recorded TV") then Goto Normal
Run ("regedit", "/s c:\windows\t.reg")
Message("CRITICAL DRIVE ERROR","V Drive not available.%@CR%Recording Path set to T:")
Exit

:Normal
; everything above this line is optional error checking
t = diskfree("t")
v = diskfree("v")
if t < v then goto vbigger
run ("regedit", "/s c:\windows\t.reg")
exit
:vbigger
run ("regedit", "/s c:\windows\v.reg")
exit