is it save to share one epg.data file between multiple vdrs over nfs? or should each client maintain its own copy?
thx ... clemens
On 11/03/07 21:55, Clemens Kirchgatterer wrote:
is it save to share one epg.data file between multiple vdrs over nfs? or should each client maintain its own copy?
Each instance of VDR writes into epg.data without any locking or so. If you set up more than one VDR that write to the same epg.data, the last one writing it will "win", and if they write at the same time, results may be undefined.
Klaus
Klaus Schmidinger Klaus.Schmidinger@cadsoft.de wrote:
Each instance of VDR writes into epg.data without any locking or so. If you set up more than one VDR that write to the same epg.data, the last one writing it will "win", and if they write at the same time, results may be undefined.
i suggest the introduction of a new command line option to switch off writing any epg data (implicitly switching off epg scan). this way only the server vdr maintains the epg and the clients only read it.
feasable?
best regards ... clemens
On 11/04/07 11:09, Clemens Kirchgatterer wrote:
Klaus Schmidinger Klaus.Schmidinger@cadsoft.de wrote:
Each instance of VDR writes into epg.data without any locking or so. If you set up more than one VDR that write to the same epg.data, the last one writing it will "win", and if they write at the same time, results may be undefined.
i suggest the introduction of a new command line option to switch off writing any epg data (implicitly switching off epg scan). this way only the server vdr maintains the epg and the clients only read it.
feasable?
The clients would only read this once at program start. I don't think this would be a good idea...
Klaus
Klaus Schmidinger Klaus.Schmidinger@cadsoft.de wrote:
i suggest the introduction of a new command line option to switch off writing any epg data (implicitly switching off epg scan). this way only the server vdr maintains the epg and the clients only read it.
The clients would only read this once at program start. I don't think this would be a good idea...
ic. so vdr only writes to the file (and reads it once at startup) and gets the EPG from internal data structures in ram on demand. so sharing epg.data is not so good of an idea.
nevertheless, running vdr in a client-server environment is becoming increasingly popular so this would be a nice feature. most notably if you inject epg from different sources (internet).
clemens
Klaus Schmidinger wrote:
i suggest the introduction of a new command line option to switch off writing any epg data (implicitly switching off epg scan). this way only the server vdr maintains the epg and the clients only read it.
The clients would only read this once at program start. I don't think this would be a good idea...
An EPG 'slave mode' could check the file timestamp of the EPG file from time to time and reload EPG on written updates, eg. once a hour or on master VDR shutdown. Would be a nice low-tech EPG distribution method.
This could even be done by a plugin: VDR runs with -E-, and the plugin watches the real epg file. From the main loop, the plugin could do something like this:
time_t lastModified = LastModifiedTime(WatchedFile); if (lastUpdate < lastModified) { cSchedulesLock SchedulesLock; if (cSchedules::ClearAll() && cSchedules::Schedules(SchedulesLock)) { cSchedules::SetEpgDataFileName(WatchedFile); cSchedules::Read(); cSchedules::SetEpgDataFileName(NULL); lastUpdate = lastModified; } }
(untested, though) Now just someone has to write the plugin around it. ;)
Cheers,
Udo
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Clemens Kirchgatterer -
Klaus Schmidinger -
Udo Richter