mirror of
https://github.com/freebsd/freebsd-src.git
synced 2024-11-28 19:52:44 +00:00
219 lines
6.2 KiB
Groff
219 lines
6.2 KiB
Groff
.\" Copyright (c) 2008 Poul-Henning Kamp
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd February 9, 2008
|
|
.Os
|
|
.Dt FIFOLOG 1
|
|
.Sh NAME
|
|
.Nm fifolog_create , fifolog_write , fifolog_read
|
|
.Nd "initialize, write, seek and extract data from a fifolog"
|
|
.Sh SYNOPSIS
|
|
.Nm fifolog_create
|
|
.Op Fl l Ar record-size
|
|
.Op Fl r Ar record-count
|
|
.Op Fl s Ar size
|
|
.Ar file
|
|
.Nm fifolog_reader
|
|
.Op Fl t
|
|
.Op Fl b Ar tstart
|
|
.Op Fl B Ar Tstart
|
|
.Op Fl e Ar tend
|
|
.Op Fl E Ar Tend
|
|
.Op Fl o Ar ofile
|
|
.Op Fl R Ar regexp
|
|
.Op Fl T Ar timefmt
|
|
.Ar file
|
|
.Nm fifolog_writer
|
|
.Op Fl w Ar write-rate
|
|
.Op Fl s Ar sync-rate
|
|
.Op Fl z Ar compression
|
|
.Ar file
|
|
.Sh DESCRIPTION
|
|
Fifologs provide a compact round-robin circular storage for
|
|
recording text and binary information to permanent storage in a bounded
|
|
and predictable fashion, time and space wise.
|
|
.Pp
|
|
A fifolog can be stored either directly on a disk partition or in a
|
|
regular file.
|
|
.Pp
|
|
The input data stream is encoded, compressed and marked up with
|
|
timestamps before it is written to storage, such that it is possible
|
|
to seek out a particular time interval in the stored data, without
|
|
having to decompress the entire logfile.
|
|
.Pp
|
|
The
|
|
.Nm fifolog_create
|
|
utility
|
|
is used to initialize the first sector of a disk device
|
|
or file system file to make it a fifolog and should be called only
|
|
once.
|
|
.Pp
|
|
Running
|
|
.Nm fifolog_create
|
|
on an existing fifolog will reset it so that
|
|
.Nm fifolog_reader
|
|
and
|
|
.Nm fifolog_writer
|
|
will not see the previous contents.
|
|
(The previous contents are not physically erased, and with a bit
|
|
of hand-work all but the first record can be easily recovered.)
|
|
.Pp
|
|
If the
|
|
.Ar file
|
|
does not already exist,
|
|
.Nm
|
|
will attempt to create and
|
|
.Xr ftruncate 2
|
|
it to the specified size, defaulting to 86400 records of 512 bytes
|
|
if the
|
|
.Fl r , l
|
|
or
|
|
.Fl s
|
|
options do not specify otherwise.
|
|
.Pp
|
|
The
|
|
.Nm fifolog_writer
|
|
utility
|
|
will read standard input and write it to the end of the fifolog
|
|
according to the parameters given.
|
|
.Pp
|
|
Writes happen whenever the output buffer is filled with compressed
|
|
data or when either of two timers expire, forcing a partially filled
|
|
buffer to be written.
|
|
.Pp
|
|
The first and faster timer,
|
|
.Fl w Ar write-rate ,
|
|
forces available data to be written
|
|
but does not flush and reset the compression dictionary.
|
|
This timer is intended to minimize the amount of logdata lost in RAM
|
|
in case of a crash and by default it fires 10 seconds after
|
|
the previous write.
|
|
.Pp
|
|
The second and slower timer,
|
|
.Fl s Ar sync-rate ,
|
|
forces a full flush and reset of the compression
|
|
engine and causes the next record written to be a synchronization
|
|
point with an uncompressed timestamp, making it possible to start
|
|
reading the logfile from that record.
|
|
By default this timer fires a minute after the previous sync.
|
|
.Pp
|
|
The
|
|
.Fl z Ar compression
|
|
option controls the
|
|
.Xr zlib 3
|
|
compression level; legal values are zero to nine which is the default.
|
|
.Pp
|
|
The
|
|
.Nm fifolog_reader
|
|
utility
|
|
will retrieve records from the fifolog according to the specified
|
|
parameters and write them either to standard output or the file specified
|
|
with
|
|
.Fl o .
|
|
.Pp
|
|
It is possible to specify a start and end time to limit the amount
|
|
of data
|
|
.Nm fifolog_reader
|
|
will report.
|
|
The lower-case variants
|
|
.Fl b
|
|
and
|
|
.Fl e
|
|
take a
|
|
.Vt time_t
|
|
value, whereas the upper-case variants
|
|
.Fl B
|
|
and
|
|
.Fl E
|
|
take human-readable specifications such as
|
|
.Dq Li "1 hour ago" .
|
|
.Pp
|
|
The
|
|
.Fl t
|
|
option forces timestamps to be formatted as
|
|
.Dq Li "YYYYMMDDhhmmss"
|
|
instead of as
|
|
.Vt time_t ,
|
|
and
|
|
.Fl T
|
|
allows the specification of an
|
|
.Xr strftime 3
|
|
formatting string.
|
|
.Pp
|
|
Finally, records can be filtered such that only records matching the
|
|
.Pq Dv REG_BASIC
|
|
regular expression specified with
|
|
.Fl R
|
|
are output.
|
|
.Sh IMPLEMENTATION NOTES
|
|
The data stored in the fifolog consists of three layers, an outer
|
|
layer that allows searches to synchronization points based on timestamps
|
|
without having to decompress and decode the actual contents, a
|
|
compression layer implemented with
|
|
.Xr zlib 3 ,
|
|
and an inner serialization and timestamping layer.
|
|
.Pp
|
|
The exact encoding is described in the
|
|
.Pa fifolog.h
|
|
file.
|
|
.Pp
|
|
Fifolog is particularly well suited for use on Flash based media, where
|
|
it results in much lower write-wear, than a file system with regular
|
|
log files rotated with
|
|
.Xr newsyslog 8
|
|
etc.
|
|
.Sh EXAMPLES
|
|
Create a fifolog with 1024*1024 records of 512 bytes:
|
|
.Pp
|
|
.Dl "fifolog_create -r 10m /tmp/fifolog"
|
|
.Pp
|
|
Write a single record to this file:
|
|
.Pp
|
|
.Dl "date | fifolog_writer /tmp/fifolog"
|
|
.Pp
|
|
Read it back with human readable timestamps:
|
|
.Pp
|
|
.Dl "fifolog_reader -t /tmp/fifolog"
|
|
.Pp
|
|
One particular useful use of
|
|
.Nm fifolog_writer
|
|
is with
|
|
.Xr syslogd 8
|
|
using a line such as this in
|
|
.Xr /etc/syslog.conf 5 :
|
|
.Pp
|
|
.Dl "*.* |fifolog_writer /var/log/syslog_fifolog"
|
|
.Sh HISTORY
|
|
The fifolog tools have been liberated from an open source
|
|
.Tn SCADA
|
|
applications called
|
|
.Dq measured ,
|
|
which monitors and controls remote radio navigation
|
|
transmitters for the Danish Air Traffic Control system.
|
|
.Sh AUTHORS
|
|
The fifolog tools were written by
|
|
.An Poul-Henning Kamp .
|