[mythtv-users] Changing filesystems?

[William Powers]

Jeff wrote:
> 
> Seeing as how I started this...my original post was flawed as pointed out by 
> Steve, I said used a lot of inodes when I really meant block pointers (was just 
> typing away).  Anyway, thanks everyone for the info, my greatest fears were 
> realized <g> and I'll probably have to find room on another box to copy off my 
> 70G worth of recordings and create the new file system.  Was hoping to skate by 
> and was looking for an easy way to change fs to no avail.
> 
> Jeff

FWIW, since this thread started, and since I too have have experienced 
problems (dropped frames) due to file deletions, I did some online 
research on web regarding linux filesystem performance.  Most of the 
published benchmarks are designed to measure raw i/o performance and, 
from those benchmarks, one would be be inclined to select ReiserFS or 
XFS.  However, the Mongo benchmark from Namesys does measure file 
deletions as one of it's performance sub-categories and in that category 
(and that category alone), JFS was the clear hands-down winner.

Based on that, I ran an experiment to compare the deletion time of a 
single 10G file on an ext3 partition and on a JFS partition.  The 
results were 10.2 seconds to delete the file on the ext3 partition and 
0.9 seconds to delete the file on the JFS partition.

Note that the time was obtained by using the following command for the 
file delete:  "hwclock;rm -f bigfile;hwclock" and then subtracting the 
two times, so there is undoubtedly a certain amount of system overhead 
in there, but it still seems clear that there is at least an order of 
magnitude improvement with JFS relative to ext3.

Since file deletion appears to be a limiting condition for a myth video 
partition, and raw i/o performance does not, I have converted my video 
partition to JFS.  Anyone who has experienced dropped frames or other 
problems due to file deletes might want to at least try using JFS in 
that role and see if it helps them.

Bill