[mythtv-users] Changing filesystems?
wepprop at sbcglobal.net
Sun Feb 8 04:33:28 EST 2004
Robert Kulagowski wrote:
> Interesting. If others care to weigh in, I can either re-write the
> "Advanced Partitioning" section in the HOWTO, or whack it completely.
> William, can you give some background on the hardware used for your
> tests? I'd be curious if this data holds up across various drive types,
> LVM, etc. (Without trying to exhaustively test all the possibilities,
> that is)
Athlon XP 1800+ on an NForce2 motherboard w/ 256M. The system is RHFC1
with Myth, ivtv, alsa, etc., installed via ATrpms, and it resides on an
ext3 partition on a Maxtor 20G, 7200 rpm drive. The video partition is
on a separate Western Digital 120G, 7200 rpm drive. I've got the
acoustic management of both drives on quiet settings for the obvious
reason. I'm not using LVM. To run the tests, I deleted enough video
files that I could move the remaining ones over to the system drive,
leaving the entire video partition free to be reformatted for the tests.
I don't claim the tests are all that precise, because I didn't hack the
kernel or do anything fancy in order to obtain extremely accurate times.
Nor did I repeat the tests enough times to really understand how the
results might vary, mostly because it takes so darn long to write the
10G file. I was really just curious to see if any of the various
filesystem's delete performance was substantially better, or worse, than
any of the others.
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.
The really ironic result from my personal perspective is that it would
appear that using the '-T largefile4' setting for ext3, which I was so
pleased with because it give me an extra 2G of storage, may well have
been responsible for all those recordings I had ruined by frame drops.
Assuming it works out, though, I could really get to like this XFS
filesystem because it appears to give me slightly more storage space
than ext3 w/ '-T largefile4' did and it has pretty fast deletes as well.
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