[mythtv-users] Changing filesystems?

[Johannes Niess]

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Am Sonntag, 8. Februar 2004 10:33 schrieb William Powers:
> It appears, based on my personal experience alone, that file deletes are
> the only system operations that can stress the hard drive enough to
> produce dropped frames.  Unfortunately, as others have pointed out,
> recordings and deletions go together in Myth.  So, unusual as it may be,
> it does make at least some sense to take file deletion performance into
> account when deciding which filesystem to use for a video partition,
> especially for people with multiple tuners.

When I think about it, we don't need to delete files when expiring but can 
write over them:

1) mv expired.file new.file
2) open new.file
A) maybe truncate (so FS info is correct)
4) write
B) maybe truncate to finished size

We just need one of A or B. Option B avoids freeing sector for the OS but 
leaves us with a undefined end of file, so jumping forward too much ends up 
in content of expired.file. Just the size difference needs to be freed (at 
end of recording) or claimed (as needed). Option A might result in much of 
the effects of deletion, but the OS could free the sectors asyncronously, 
after returning from the truncation call. Timing results of "echo > 
10gb.file" would be interesting.

Johannes Nieß
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