[mythtv-users] Information/Recommendations on a new MythTV

[Leighton Brough]

>> So as long as I don't delete while recording I should be fine. However I still think I want to go XFS if I can easily with the debian network installer.
>>     
> I recently did my own benchmarks creating and deleting a 4 GB file on 
> EXT3, Reiser4, JFS, and XFS. I unfortunately discarded the numbers after 
> I made my choice, so this is based off of memory. With both Reiser4 and 
> EXT3, the 4 GB file could be created in about 3.5 minutes, with Reiser4 
> being slightly faster. JFS and XFS took anywhere from 4 to 5 minutes to 
> create the file, with JFS being slightly faster. EXT3 took about 14 
> seconds to delete the file, Reiser4 took about 4 seconds to delete the 
> file, and both JFS and XFS took something like 0.2 seconds to delete the 
> file.
>
> Despite the timings, I chose EXT3 for several reasons.
> 1) I'm using LVM, so that I can easily swap in and out hard drives, 
> depending on use. All file systems allow you to grow a partition to use 
> up the space on a new hard drive, but only EXT3 and Reiser4 allow you to 
> shrink a partition, in case I'd want to remove a hard drive.
> 2) MythTV 0.20 (0.19?) now has a slow-delete feature for EXT3 file 
> systems, so that it doesn't lock up the machine for 14 seconds when it 
> deletes a file.
> 3) EXT3 is in more common use than Reiser4 and seems to be more heavily 
> supported.
>   
Maybe 6 months ago or so I change my mythtv video partition from EXT3 to 
XFS. This certainly did solve the slow file deletion problem, and 
eliminate really tedious fscks on boot. But far more importantly, this 
FS seems to have far better read/write performance than EXT3 for an 
application like myth. This change was without doubt the most 
significant performance improvement I've achieved for my MythTV system.

I found using XFS was the final nail in the coffin for my jerky HD 
playback issues, particularly when recording is happening at the same 
time (I do have a new problem with jerky HD that's related to 
suspend-to-ram, but that's nothing to do with the FS). Using EXT3 when 
attempting to watch two HD programs in the picture-in-picture mode, the 
display of both was so jerky it was completely unwatchable, sometimes 
taking many seconds between frames. With XFS the playback in main window 
is smooth, with only occasionally dropped frames in the smaller window. 
Similarly, I can get away with more simultaneous recording and 
commercial flagging jobs with XFS on my combined BE/FE, than was ever 
possible using EXT3.

YMMV, but I wouldn't dream of setting up a MythTV box now without using 
XFS (or perhaps JFS, which is presumably similar) for the video 
partition. It's behaved faultlessly in terms of robustness too: when 
experimenting with suspend-to-ram, I've had to hit the reset button on 
many occasions but have never had any corruption (so far at least :-)

Leighton