Current implementations of NFS on Linux have a decent lock mechanism
(as far as I know). You'll have to check your NAS device how does it
handle NFS locking.
But, if your NFS device is a complete box and not just a disk array
with an ethernet card, you will be better creating a small
client-server protocol over TCP.
Darío
On Dec 19, 2007 6:04 AM, Trilok Soni <[EMAIL PROTECTED]> wrote:
> Hi John,
>
> On Dec 18, 2007 11:53 PM, John Stanton <[EMAIL PROTECTED]> wrote:
> > Sqlite depends upon POSIX file locks. It is no better or no worse than
> > the POSIX lock implementation on your platform.
>
> Thanx for the reply. My platform is based on Linux running on ARM9, with
> having 128MB of the flash on it. The captured video from analog/IP camera
> will be stored on the NAS storage device connected to it through network,
> which
> gets mounted to the filesystem using NFS. So, the database file containing
> these
> videos meta information will be stored on NAS device, not on the flash
> partition,
> as flash is used to keep programs binaries and the size constraint.
>
> >
> > We use Sqlite in a multi-user environment without dependency oin the
> > POSIX locks by embedding it in a server using HTTP when it is on a
> > remote machine. We get the small footprint and simoplicity of Sqlite
> > and get no multi-user glitches regardless of platform.
>
> I am not able to understand, what you mean here by "embedding sqlite in a
> server using HTTP when it is on a remote machine". In our project scenario,
> we do have remote interface of this platform using embedded webserver running
> on the device (e.g. boa/lighthttpd/webapp) and we want to show various
> information
> about these videos on the webpage by searching this file database
> residing on the NAS.
>
> Only confusion for selecting SQLite came here is, because we are not storing
> this database on the local flash on the device, but on the NFS mounted
> NAS device,
> which gets accessed/configured through web-interface provided by the
> device through
> some embedded webserver as explained in the earlier paragraph. And
> SQLite FAQs I have
> pointed mentions that there could be problem in accessing the database
> over the NFS,
> this is where I got confused and unable to decide to go for SQLite or not.
>
> --
> --Trilok Soni
>
>
>
> >
> >
> > Trilok Soni wrote:
> > > Hi,
> > >
> > > I am evaluating SQLite for the design of the surveillance camera/DVR
> > > product based on Linux, which stores its captured
> > > analog/IP camera streams to the NAS storage device(s). To facilitate
> > > faster search/scanning of those media files
> > > containing many days of videos spread over multiple files, we plan to
> > > keep the metadata of those videos
> > > in some file format/database stored on NAS itself, so that
> > > search/analysis mechanism just go through this
> > > database to locate exact file with some search criteria like
> > > time/data/camera/alarms/events etc.
> > >
> > > While reading the SQLite documentation I came to following FAQ, where
> > > it lists that SQLite as application file format,
> > > may not scale well to the NFS/Neworked attached drives due to the
> > > locking problems.
> > >
> > > http://www.sqlite.org/faq.html
> > > Refer 5th question.
> > > (5) Can multiple applications or multiple instances of the same
> > > application access a single database file at the same time?
> > >
> > > Is there any other way to work around this problem and use SQLite as
> > > application file format in the above scenario. See that Linux
> > > will run on the ARM9 having video processing done on specialized DSP.
> > >
> >
> >
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