[mythtv-users] USB 2.0 Drive Performance Issues
drew at mykitchentable.net
Tue Apr 15 17:15:01 UTC 2008
On 4/15/2008 3:45 AM Nick Morrott said the following:
> On 15/04/2008, Drew Tomlinson <drew at mykitchentable.net> wrote:
>> I'm surprised this would affect playback as now recordings are on a
>> separate drive. Maybe USB 2.0 requires more CPU than ATA drives with
>> DMA enabled? Can anyone explain this behavior? I'm just curious as I
>> still intend to install my other drives and move the external to SATA.
> USB devices can use high levels of CPU during transfers. A DMA-enabled
> ATA disk should only use minimal CPU. Also don't forget that whenever
> you are playing back video or using MythWeb, the MySQL database is
> being read at the same time. If performance still suffers when you
> have your eSATA disk online (I'd guess it will be better than USB) and
> it's due to disk I/O rather than CPU, you could move your database to
> another spindle.
Thanks for your reply. Just to be clear, the OS, MySQL database, and
everything except recordings are on an ATA-133 drive. It's only the
recordings that are on the USB. Thus I am still confused as to why
recording playback would have pauses and skips when using mythweb unless
it's just CPU contention. mythweb should not be accessing the
recordings drive, correct?
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