Date: Wed, 6 May 2020 15:19:16 -0500 From: Valeri Galtsev <galtsev@kicp.uchicago.edu> To: freebsd-questions@freebsd.org Subject: Re: redesignde the unix-like system directory Message-ID: <3f899735-1ed2-105c-1483-0450b8dcc7a3@kicp.uchicago.edu> In-Reply-To: <20200506134457056426360@bob.proulx.com> References: <83788746a7d8a802d8af4b582e00827166febd1a.camel@tom.com> <CAEJNuHzCcqR0-v_SEPT4QWai1owzL_41M-YN3fTS_YGHN0jwFg@mail.gmail.com> <9a387b42-8da5-2968-24ba-754c3e461252@kicp.uchicago.edu> <20200506151230.GI82984@trajan.stk.cx> <c3f5a607-760d-8a85-c0f3-e72ee6b9a3dc@tundraware.com> <20200506134457056426360@bob.proulx.com>
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On 5/6/20 2:55 PM, Bob Proulx wrote: > Tim Daneliuk wrote: >> Arne Steinkamm wrote: >>>>> /cloud, various cloud applications >>>>> /net, network information and server information, etc. >>> Looking at a flat layout like this one gives me a feeling, that >>> most people forgot that it's a real bad idea to have a >>> external mounted directory in the root directory... easy way to make >>> a system unresponsive in case of a network problem. >> >> Can you say a bit more about why this is so? > > Assume NFS for simplicity. A mount point at the /nfsmount1 directory. > Then run "ls -l /". That needs to stat(2) each entry in / and hits > /nfsmount1 Do people really do that? I kind of since forever use automounter or similar, net mounts are in subdirectories of /net and - this is what _I_ do, not elegant thing, but convenient for my users - I make directories in / named after names of cross mounted machines, and put there symlinks to where automounter will mount exported from these machines directories, like /machine1name/data1 --> ../mnt/machine1name/data1 Never had trouble you describe, and nicety of automounter is "nothing gets hang": once NFS server doesn't respond, mounts are unmounted seamlessly by automounter. And are mounted again when someone tries to access them and server is accessible. Valeri > with stat(2) which if the nfs server is not responding > cannot return an answer to the query. A lot of daemons and cron jobs > will assume that the file system root and all entries in there are > available and will trigger this problem as a byproduct of their > operations. I am just describing "ls -l" as the simplest way to > trigger the issue. "NFS server not responding." This can be a reason > for a system load of hundreds or thousands as process slots fill up > with stuck processes blocked waiting for I/O from an unresponsive server. > > However in the proposal I think the entries I quoted were for use as a > subdirectory and not to have a mount point directly in root. > >>> I keep the traditional filesystem layout > > +1. I prefer the traditional file system organization. > > Bob > _______________________________________________ > freebsd-questions@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org" > -- ++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++
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