Re: Building off Medusa

[Seth Nickell <snickell stanford edu>]

On Thu, 2003-04-10 at 07:02, Manuel Amador (Rudd-O) wrote:
> >
> >
> > Just so you know... Incremental indexing won't be possible using libfam.
> > FAM will not scale to monitoring over about 500 files, so you definitely
> > will not be able to get change notification on all the files on a disk.
> > I would love a way to register with the kernel to be notified whenever
> > *any* file changes, but I don't believe there is such a mechanism.
> >
> Oh, but it does, and it does well (at least on Linux and Solaris).  I 
> just got a command-line tool which reports on stdout all files changed.  
> You run it with a directory or file as the sole argument, and it spits 
> out all modified files' paths, half a second after they're modified.  
> Fam does *not* monitor *each* file.  I don't know how it does, but it 
> doesn't watch every file.  If it would, I would agree with you.

You can add FAM (with dnotify running underneath) monitors to every
directory on your system without problems? On my system FAM starts
having trouble around several hundred directories. 

FAM does not support recursive monitoring, which means you have to add a
monitor for every directory to receive notification of changes to those
files. According to the FAM FAQ, you can only have 1024 active
"requests", which means you can only monitor up to 1024 directories. My
computer has more than 30000 directories... so I don't see how it would
be possible to use FAM to receive notification of changes across my
whole filesystem.

-Seth