[mythtv-users] scan for changes

[Joe Mythtv]

My content is all local to a single backend. It's not striped across an
array, it all lives on two 5400rpm spindles. Maybe the issue is volume? It
takes me about 35 seconds to rescan 15k pictures, 15k mp3s, and 10k video
files.

As Mark mentioned, linux caching could be the reason some scans are much
faster - if I clear out the cache (by rebooting or with echo 1 >
/proc/sys/vm/drop_caches) the scan takes about 5 minutes to finish. I wish
there were a command line way to initiate the scan - I could run my own
script to look at the 'new footage' folder and rescan when I see new files.


On Sun, Mar 25, 2012 at 7:13 PM, Mark Lord <mythtv at rtr.ca> wrote:

> On 12-03-25 07:07 PM, Raymond Wagner wrote:
> > On 3/25/2012 18:27, Joe Mythtv wrote:
> >> is it possible to run a 'scan for changes' of the video library in the
> background? it can take
> >> several minutes to run so it is obtrusive to run everytime i upload
> home videos to my DVR (when
> >> family members want to see footage of the kids, they want it ASAP...)
> >> maybe there's a way to run it only for a specific directory to which I
> upload files more frequently?
> >
> > With a few thousand videos spread across multiple drives and arrays,
> performing a scan of the Video
> > Library only takes me a couple seconds.  Any new content added needs to
> be hashed, but you're
> > talking about reading 64KB from the front and back of a file.  Not
> something time intensive for even
> > dozens of new files.  If you have the batch metadata grabber enabled,
> that can take some time
> > churning through the new content, but that is run in the background and
> is going to turn up empty on
> > home videos anyway.
> >
> > If your scans are taking several minutes to run each time, there is
> something misconfigured on your
> > system.  Is this content local to one of your backends, or on a remote
> network share?  There is a
> > known issue where CIFS shares, and especially deeply nested ones, take
> an inordinately long time to
> > scan.
>
>
> The first scan after booting may take some time.
> After that, the kernel will have much of it cached
> for future scans, depending on VM activity.
>
> So it's not always mere seconds.  Here, it seems to take about 30 seconds
> to scan about 2400 videos.  Subsequent runs take perhaps 2-3 seconds.
>
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