[mythtv-users] Which filesystem deletes large files the fastest?

[Brandon Beattie]

>From my browsing I decied upon JFS because at the time (2003) it had the
lowest CPU overhead when manipulating the filesystem.  My setup is 5
maxtor 200GB 7200RPM drives (mb cache each).  I've found that it takes
anywhere from half a second to 2 seconds to delete from 500mb to over
400GB files(HD from the olympics).  I've concluded that most of the time
used for a "delete recording" is actually in myth and the gui, not
deleting frmo disk.  I still regularly have 100GB+ files (golf/nascar)
and with JFS they are almost instantly gone, rarely do I have a file
that takes long enough to delete that I wish it was faster - Maybe 15
times in last year of using Myth).

I've wanted to try out other FS's such as the new Reiser and XFS (I did
try this before but JFS somehow became my choice).  I'm trying to save
some money up to build a backend/frontend setup when I get my HD-3000
card.  Most performance problems I see for HD content comes from running
a backend and frontend on the same box that has more than 1 or 2 HD 
tuners.  I've been happy with JFS, I'll try the others for fun.  I
personally believe your motherboard's BUS will make more of a
difference than FS type when comparing JFS,XFS, Reiser, Ext3.  My system
runs at about 60MB/s write and 95MB/s read.  Using 4 HD tuner cards
that's at most 80Mb/s (bits now, not bytes).  Not doing raid/striping
you can get about 20-30MB or 160/240Mb/s, plenty fast for a HTPC.  If
you start using your bus for more than just disk, that's when you see
stuttering video problems or files taking longer to delete. AGP can 
take quite a lot of bandwidth.

Other improvements for deleting files faster would be to have your
recordings on their own disk.  Nothing kills performance like having a
hard drive seeking all over the thing.  Do a find / if you have a lot
of data on the drive (or cat a file to /dev/null) and then try deleting
another large file and see how much how much longer it takes to delete
it.

As for not losing data, you shouldn't regardless the file size if you're
using a journaling FS.

My personal question is has anyone done benchmarks to see which FS
performs better when the CPU or system bus is maxed out?

--Brandon

On Tue, Oct 26, 2004 at 01:28:36PM -0400, David Muench wrote:
> > Which FS deletes large files the fastest, without loosing too much when
> > it crashes?
> 
> I'm very pleased with JFS, it seems to delete things instantly. XFS also
> worked very well for me in the past, but when I rebuilt my backend I
> decided to try JFS this time around.
> 
> Dave
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