[mythtv-users] File System Recommendation?

Jesse Guardiani jesse at wingnet.net
Mon Apr 3 05:45:28 UTC 2006


On Monday 03 April 2006 12:10 am, f-myth-users at media.mit.edu wrote:
> The problem isn't making the -user- wait for the disk, it's making
> -Myth- wait for the disk.
> 
> While ext3fs is deleting a file, all other writers block.  If you're
> currently writing a stream (or several) to the same filesystem, -they-
> will block.  Eventually your buffers will overflow, and you'll lose
> data, and your recordings in progress will have glitches in them.

Hmmmm... I wonder if reiserfs exhibits the same behavior? I'm running
2x250G SATA in a RAID-1 on my combined front/backend, and I don't
*think* I've ever had that happen.

I've had recordings with glitches in them, but I'm pretty sure they
were caused by extremely high CPU load (when I'm playing games usually).

Performance seems pretty decent.


> (And I won't go anywhere near ReiserFS, because its semantics are
> inherently broken in the face of machine resets or kernel crashes,
> leading to good metadata but the contents of open files swapped among
> each other---no thanks.)

I run reiserfs on at least 7 production machines without a single issue. 
They all run modern kernels (2.6.13 or 2.6.15) and range from a SMP P2
400mhz to uniprocessor/SMP P3 1ghz to 3ghz P4s. One machine is an 
unreliable P3-M laptop. The hardware seems to have cache issues, and 
it'll lock up now and then. But I've never lost a file when it recovers.

My only advice is to stay away from PREEMPT like the plague. Some disk 
drivers can't handle it and will corrupt your data under load. I've 
experienced this first hand and disabling PREEMPT has solved the 
problem 100%. Or perhaps that's an issue with reiserfs itself? I don't
know.

I'm not saying that reiserfs is the way to go. In fact, I'd like to 
give JFS or XFS a try myself to see how they compare. But I don't 
think you'll have any reliability issues with reiserfs so long as
you use a kernel >= 2.6.13 and disable PREEMPT. I've had good luck 
with it for about 2 years now myself.


-- 
Jesse Guardiani
Programmer/Sys Admin
jesse at wingnet.net


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