3 cycbuff.conf - Configuration file for INN CNFS storage method
7 This file defines the cyclical buffers that make up the storage pools for
8 CNFS (Cyclic News File System). Some options controlling the behavior of
9 the CNFS storage system can also be set here. F<cycbuff.conf> is required
10 if the CNFS (Cyclic News File System) storage method is used. INN will
11 look for it in I<pathetc> (as set in F<inn.conf>).
13 For information about how to configure INN to use CNFS, see
16 Blank lines and lines beginning with a hash sign (C<#>) are ignored. All
17 other lines must be of one of the following forms:
19 cycbuffupdate:<interval>
20 refreshinterval:<interval>
21 cycbuff:<name>:<file>:<size>
22 metacycbuff:<name>:<buffer>[,<buffer>,...][:<mode>]
24 (where items enclosed in [] are optional). Order is mostly not
25 significant, but all I<cycbuff> lines must occur before all I<metacycbuff>
26 lines. Long lines can be continued on the next line by ending the line
27 with a backslash (C<\>).
31 =item cycbuffupdate:<interval>
33 Sets the number of articles are written before the cycbuff header is
34 written back to disk to <interval>. Under most operating systems, the
35 header doesn't have to be written to disk for the updated data to be
36 available to other processes on the same system that are reading articles
37 out of CNFS, but any accesses to the CNFS cycbuffs over NFS will only see
38 the data present at the last write of the header. After a system crash,
39 all updates since the last write of the CNFS header may be lost. The
40 default value, if this line is omitted, is 25, meaning that the header is
41 written to disk after every 25 articles stored in that cycbuff.
43 =item refreshinterval:<interval>
45 Sets the interval (in seconds) between re-reads of the cycbuff header to
46 <interval>. This primarily affects B<nnrpd> and controls the frequency
47 with which it updates its knowledge of the current contents of the CNFS
48 cycbuffs. The default value, if this line is omitted, is 30.
50 =item cycbuff:<name>:<file>:<size>
52 Configures a particular CNFS cycbuff. <name> is a symbolic name for the
53 buffer, to be used later in a metacycbuff line. It must be no longer than
54 seven characters. <file> is the full path to the buffer file or block
55 device, and must be no longer than 63 characters. <size> is the length of
56 the buffer in kilobytes (1KB is 1024 bytes). If <file> is not a block
57 device, it should be <size> * 1024 bytes long.
59 =item metacycbuff:<name>:<buffer>[,<buffer>,...][:<mode>]
61 Specifies a collection of CNFS buffers that make up a single logical
62 storage location from the perspective of INN. Metacycbuffs are referred
63 to in F<storage.conf> as storage locations for articles, so in order to
64 actually put articles in a cycbuff, it has to be listed as part of some
65 metacycbuff which is then referenced in F<storage.conf>.
67 <name> is the symbolic name of the metacycbuff, referred to in the options
68 field of cnfs entries in F<storage.conf>. <buffer> is the name of a
69 cycbuff (the <name> part of a cycbuff line), and any number of cycbuffs
70 may be specified, separated by commas.
72 If there is more than one cycbuff in a metacycbuff, there are two ways
73 that INN can distribute articles between the cycbuffs. The default mode,
74 INTERLEAVE, stores the articles in each cycbuff in a round-robin fashion,
75 one article per cycbuff in the order listed. If the cycbuffs are of
76 wildly different sizes, this can cause some of them to roll over much
77 faster than others, and it may not give the best performance depending on
78 your disk layout. The other storage mode, SEQUENTIAL, instead writes to
79 each cycbuff in turn until that cycbuff is full and then moves on to the
80 next one, returning to the first and starting a new cycle when the last
81 one is full. To specify a mode rather than leaving it at the default, add
82 a colon and the mode (INTERLEAVE or SEQUENTIAL) at the end of the
87 B<innd> only reads F<cycbuff.conf> on startup, so if you change anything
88 in this file and want B<innd> to pick up the changes, you have to stop and
89 restart it. C<ctlinnd reload all ''> is not sufficient.
91 When articles are stored, the cycbuff into which they're stored is saved
92 as part of the article token. In order for INN to retrieve articles from
93 a cycbuff, that cycbuff must be listed in F<cycbuff.conf>. However, if
94 INN should not write to a cycbuff, it doesn't need to be (and shouldn't
95 be) listed in a metacycbuff.
97 This provides an easy way to retire a cycbuff. Just remove it from its
98 metacycbuff, leaving in the cycbuff line, and restart B<innd> (with, for
99 example, C<ctlinnd xexec innd>). No new articles will be put into the
100 cycbuff, but neither will any articles expire from it. After you no
101 longer need the articles in the cycbuff, just remove it entirely from
102 F<cycbuff.conf>. Then all of the articles will appear to have been
103 deleted to INN, and the next nightly expire run will clean up any
104 remaining references to them.
106 Adding a new cycbuff just requires creating it (see below), adding a
107 cycbuff line, adding it to a metacycbuff, and then restarting B<innd>.
109 =head1 CREATING CYCBUFFS
111 When creating a new cycbuff, there are two different methods for creating
112 the buffers in which the articles will be stored.
118 Create a large file on top of a regular file system. The easiest way to
119 do this is probably with dd(1), using a command like:
121 dd if=/dev/zero of=/path/to/cycbuff bs=1024 count=<size>
123 where <size> is the size from the cycbuff line in F<cycbuff.conf>.
124 F<INSTALL> contains a script that will generate these commands for you
125 from your F<cycbuff.conf> file.
127 This is the simplest method, but has the disadvantage that very large
128 files on regular file systems can be fairly slow to access, particularly
129 at the end of the file, and INN incurs unnecessary file system overhead
130 when accessing the cycbuff.
134 Use block devices directly. If your operating system allows you to call
135 mmap() on block devices (Solaris and recent versions of Linux do, FreeBSD
136 at last report does not), this is the recommended method since you can
137 avoid all of the native file system overhead. Note, however, that each
138 cycbuff cannot be larger than 2GB with this method, so if you need a lot
139 of spool space, you may have to go back to disk files.
141 Partition the disk to make each partition equal to or smaller than 2GB.
142 If you're using Solaris, set up your partitions to avoid the first
143 cylinder of the disk (or otherwise the cycbuff header will overwrite the
144 disk partition table and render the cycbuffs inaccessible). Then, create
145 device files for each block device you're going to use.
147 It's not recommended to use the block device files in F</dev>, since the
148 news system doesn't have permission to write to them and changing the
149 permissions of the system device files may affect something else.
150 Instead, use mknod(1) to create a new set of block devices (in somewhere
151 like I<pathspool>/cycbuffs that's only writable by the news user). To do
152 this, run C<ls -Ll> on the devices in F</dev> that correspond to the block
153 devices that you want to use. The major and minor device numbers are in
154 the fifth and sixth columns (right before the date), respectively. Then
157 mknod <file> b <major> <minor>
159 where <file> is the path to the device to create (matching the <file> part
160 of the cycbuff line) and <major> and <minor> are the major and minor
161 device numbers as discovered above.
163 Here's a short script to do this when given the path to the system device
167 base=`echo "$1" | sed 's%.*/%%'`
168 major=`ls -Ll "$1" | awk '{print $5}' | tr -d ,`
169 minor=`ls -Ll "$1" | awk '{print $6}`
170 mkdir -p /usr/local/news/spool/cycbuffs
171 mknod /usr/local/news/spool/cycbuffs/"$base" b "$major" "$minor"
172 chown news:news /usr/local/news/spool/cycbuffs/"$base"
173 chmod 644 /usr/local/news/spool/cycbuffs/"$base"
175 Make sure that the created files are owned by the news user and news
176 group, as specified at configure time (the default being C<news> for
177 both). Also make sure that the permissions on the devices allow the news
178 user to read and write, and if you want other users on the system to be
179 able to use B<sm> to retrieve articles, make sure they're world-readable.
183 Once you have everything configured properly and you start B<innd>, you
184 should see messages in F<news.notice> that look like:
186 innd: CNFS-sm No magic cookie found for cycbuff ONE, initializing
188 where ONE will be whatever you called your cycbuff.
192 Written by Katsuhiro Kondou <kondou@nec.co.jp> for InterNetNews.
193 Rewritten into POD by Russ Allbery <rra@stanford.edu>.
195 $Id: cycbuff.conf.pod 7860 2008-06-07 12:46:49Z iulius $
199 ctlinnd(8), innd(8), nnrpd(8), sm(1), storage.conf(5)