[vdr] Re: two or more harddrives and performance (filesystem streaming performance benchmark)

[Emil Naepflein <Emil.Naepflein@philosys.de>]

Hi Jon,

> Please let me know if you have any comments about these results or if 
> you have some interesting results of your own.

that is very very interesting data! 

I have tested the filesystem performance myself when I recreated them on
my 1.2 TB server with four DVB cards. But I did only tests with bonnie
which doesn't write interleaved files. I decided to use ext3 (journaled)
because it was fasted on single read and write tests and a good
compromise on file creation and deletions. Since I use ext3 I have
ocassional performance problems when doing a lot of recordings
concurrently and cutting. I contributed this performance problems to the
fact that VDR is reading/writing the data through the block cache, which
is a further problem that should be fixed.

The problem may also be made worse by the fact that I have changed the
file allocation algorithm to fill a disk first before using the next one
to keep the files of recordings together, whereas vanilla VDR
distributed concurrent recordings over the disks automatically.

I will now change the primary filesystems to xfs which is not so good on
file deletions and see how the system behaves then.

Thanks,
Emil


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