.\" $Id: preend.man,v 3.7 2012/09/05 23:38:14 ksb Exp $
.\" by MatthewBradburn and Kevin Braunsdorf
.\" $Compile: Display%h
.\" $Display: groff -Tascii -man %f | ${PAGER:-less}
.\" $Install: %b -mDeinstall %o %f && cp %f $DESTDIR/usr/local/man/man8/preend.8
.\" $Deinstall: ${rm-rm} -f $DESTDIR/usr/local/man/[cm]a[nt][18]/preend.8*
.TH PREEND 8L LOCAL
.SH NAME
preend - tomb preening daemon
.SH SYNOPSIS
\fBpreend\fP [\fB\-1Rdnp\fP] [\fB\-s\fP\~\fIminutes\fP] [\fItombs\fP]
.br
\fBpreend\fP \fB\-h\fP
.br
\fBpreend\fP \fB\-V\fP

.SH DESCRIPTION
Files destroyed by the library calls in the entombing library, libtomb.a,
are placed in a tomb subdirectory at the root of each file system.
The preening daemon, \fIpreend\fP, removes old files from each of these tombs.
.PP
The policy used to age files is based on the percentage of the file system
in use.
If the file system in question is less
than 90% full, files are left in the tomb for 24 hours, minus one second
for each two bytes of the file.  If the file system is between 90 and 95% full,
files last 6 hours, again adjusted for file size.  If the file system
is between 95 and 100% full, files last 15 minutes.  If the file system
is more than 100% full, all files are removed
at about 5 minute intervals.
.PP
An exception is made for files named \*(lqa.out\*(rq or
\*(lqcore\*(rq and file names beginning with a \*(lq#\*(rq or
ending in \*(lq.o\*(rq or
\*(lq~\*(rq, which are left in the tomb for at most \fIminutes\fP minutes.
Some other files might be removed with such prejudice on a site by site
basis (gmon.out would be another example).
.SH OPTIONS
.TP
.nf
\fB\-1\fP
.fi
Just run one preen run, synchronously.
.TP
.nf
\fB\-d\fP
.fi
Turn on debugging output.  \fIPreend\fP writes some of its actions to
stdout during each run.
.TP
.nf
\fB\-h\fP
.fi
Output a brief help message.
.TP
.nf
\fB\-n\fP
.fi
Do not really take any actions.  Useful under \fB\-d\fP to see
what \fIpreend\fP would do without messing up the tombs.
.TP
.nf
\fB\-p\fP
.fi
Run one \fIpreend\fP process per file system.
Since each daemon will \fBchdir\fP(2) into its tomb before it begins
to preen, this will save many, many namei's in the kernel.
Under DYNIX, and other symmetric multi-processor systems, \fIpreend\fP
may take advantage of more than one CPU with this option to provide
closer to optimal service.
.TP
.nf
\fB\-R\fP
.fi
Remove empty crypts from the tombs.  This options should be used
with care as it can race with running \fIentomb\fPs and \fIpreends\fP to cause
strange error messages.  The superuser might remove empty tombs after
removing many user accounts (at the end of a school term, or large
project) this speeds \fIpreend\fPs normal operation slightly.
.TP
.nf
\fB\-s\fP \fIminutes\fP
.fi
Sleep \fIminutes\fP between file system checks
(the default is 5 or 15 minutes).
.TP
.nf
\fB\-V\fP
.fi
Show version information for \fIpreend\fP and which tombs are
on the local machine.
.TP
.nf
\fItombs\fP
.fi
If any tombs are given, \fIpreend\fP preens only those tombs.
This is the only way to force a local \fIpreend\fP to preen an
NFS mounted tomb (it is assumed that the remote host will preen
its own tombs).

.SH EXAMPLES
.TP
preend \-dn1
Show what actions \fIpreend\fP will take on the next pass through
the tombs (if it were to run immediately).
.TP
preend \-p
Start a daemon for each tomb on this machine (the normal start up
at PUCC).
.TP
preend \-V
Show the version of \fIpreend\fP and tombs on this machine.
.TP
preend /share/tomb
Force preend to preen for the file system \fI/share\fP.
If, for example, the file system is NFS mounted from
another machine \fIpreend\fP doesn't start a daemon for this tomb by default.
.SH BUGS
.PP
The policy for aging files should not be so hard coded.
The threshold for each level of policy could be specified
with command line option(s).
.SH AUTHORS
Matthew Bradburn, Purdue University Computing Center
.br
Kevin Braunsdorf, entomb at ksb dot NPCGuild.orgSPAMmeNOT
.SH "SEE ALSO"
.hlm 0
unrm(1l), libtomb(3X), file_recover(7l), entomb(8l), rmfile(1l)