1CYCBUFF.CONF(5) InterNetNews Documentation CYCBUFF.CONF(5)
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6 cycbuff.conf - Configuration file for INN CNFS storage method
7
9 This file defines the cyclical buffers that make up the storage pools
10 for CNFS (Cyclic News File System). Some options controlling the
11 behavior of the CNFS storage system can also be set here. cycbuff.conf
12 is required if the CNFS (Cyclic News File System) storage method is
13 used. INN will look for it in pathetc (as set in inn.conf).
14 CNFS stores articles in logical objects called metacycbuffs. Each
16 metacycbuff is in turn composed of one or more physical buffers called
17 cycbuffs. As articles are written to the metacycbuff, each article is
18 written to the next cycbuff in the list in a round-robin fashion
19 (unless "sequential" mode is specified, in which case each cycbuff is
20 filled before moving on to the next). This is so that you can
21 distribute the individual cycbuffs across multiple physical disks and
22 balance the load between them. Note that in order to use any cycbuff
23 larger than 2 GB, you need to build INN with the --enable-largefiles
24 option.
25 For information about how to configure INN to use CNFS, see
27 storage.conf(5).
28 Blank lines and lines beginning with a hash sign ("#") are ignored.
30 All other lines must be of one of the following forms:
31 cycbuffupdate:<interval>
33 refreshinterval:<interval>
34 cycbuff:<name>:<file>:<size>
35 metacycbuff:<name>:<buffer>[,<buffer>,...][:<mode>]
36 (where items enclosed in [] are optional). Order is mostly not
38 significant, but all cycbuff lines must occur before all metacycbuff
39 lines. Long lines can be continued on the next line by ending the line
40 with a backslash ("\").
41 cycbuffupdate:<interval>
43 Sets the number of articles written before the cycbuff header is
44 written back to disk to <interval>. Under most operating systems,
45 the header doesn't have to be written to disk for the updated data
46 to be available to other processes on the same system that are
47 reading articles out of CNFS, but any accesses to the CNFS cycbuffs
48 over NFS will only see the data present at the last write of the
49 header. After a system crash, all updates since the last write of
50 the CNFS header may be lost. The default value, if this line is
51 omitted, is 25, meaning that the header is written to disk after
52 every 25 articles stored in that cycbuff.
53 refreshinterval:<interval>
55 Sets the interval (in seconds) between re-reads of the cycbuff
56 header to <interval>. This primarily affects nnrpd and controls
57 the frequency with which it updates its knowledge of the current
58 contents of the CNFS cycbuffs. The default value, if this line is
59 omitted, is 30.
60 cycbuff:<name>:<file>:<size>
62 Configures a particular CNFS cycbuff. <name> is a symbolic name
63 for the buffer, to be used later in a metacycbuff line. It must be
64 no longer than seven characters. <file> is the full path to the
65 buffer file or block device, and must be no longer than 63
66 characters. <size> is the length of the buffer in kilobytes (1 KB
67 is 1024 bytes). If <file> is not a block device, it should be
68 <size> * 1024 bytes long.
69 If you're trying to stay under 2 GB, keep your sizes below 2097152.
71 metacycbuff:<name>:<buffer>[,<buffer>,...][:<mode>]
73 Specifies a collection of CNFS buffers that make up a single
74 logical storage location from the perspective of INN. Metacycbuffs
75 are referred to in storage.conf as storage locations for articles,
76 so in order to actually put articles in a cycbuff, it has to be
77 listed as part of some metacycbuff which is then referenced in
78 storage.conf.
79 <name> is the symbolic name of the metacycbuff, referred to in the
81 options: field of "cnfs" entries in storage.conf. It must be no
82 longer than eight characters. <buffer> is the name of a cycbuff
83 (the <name> part of a cycbuff line), and any number of cycbuffs may
84 be specified, separated by commas.
85 If there is more than one cycbuff in a metacycbuff, there are two
87 ways that INN can distribute articles between the cycbuffs. The
88 default mode, "INTERLEAVE", stores the articles in each cycbuff in
89 a round-robin fashion, one article per cycbuff in the order listed.
90 If the cycbuffs are of wildly different sizes, this can cause some
91 of them to roll over much faster than others, and it may not give
92 the best performance depending on your disk layout. The other
93 storage mode, "SEQUENTIAL", instead writes to each cycbuff in turn
94 until that cycbuff is full and then moves on to the next one,
95 returning to the first and starting a new cycle when the last one
96 is full. To specify a mode rather than leaving it at the default,
97 add a colon and the mode ("INTERLEAVE" or "SEQUENTIAL") at the end
98 of the metacycbuff line.
99 innd only reads cycbuff.conf on startup, so if you change anything in
101 this file and want innd to pick up the changes, you have to use
102 "ctlinnd xexec innd"; "ctlinnd reload all ''" is not sufficient.
103 When articles are stored, the cycbuff into which they're stored is
105 saved as part of the article token. In order for INN to retrieve
106 articles from a cycbuff, that cycbuff must be listed in cycbuff.conf.
107 However, if INN should not write to a cycbuff, it doesn't need to be
108 (and shouldn't be) listed in a metacycbuff.
109 This provides an easy way to retire a cycbuff. Just remove it from its
111 metacycbuff, leaving in the cycbuff line, and restart innd (with, for
112 example, "ctlinnd xexec innd"). No new articles will be put into the
113 cycbuff, but neither will any articles expire from it. After you no
114 longer need the articles in the cycbuff, just remove it entirely from
115 cycbuff.conf. Then all of the articles will appear to have been
116 deleted to INN, and the next nightly expire run will clean up any
117 remaining references to them.
118 Adding a new cycbuff just requires creating it (see below), adding a
120 cycbuff line, adding it to a metacycbuff, and then restarting innd.
121
123 When creating a new cycbuff, there are two different methods for
124 creating the buffers in which the articles will be stored.
125 1. Create a large file on top of a regular file system. The easiest
127 way to do this is probably with dd(1), using a command like:
128 dd if=/dev/zero of=/path/to/cycbuff bs=1024 count=<size>
130 where <size> is the size from the cycbuff line in cycbuff.conf.
132 INSTALL contains a script that will generate these commands for you
133 from your cycbuff.conf file.
134 This is the simplest method, but has the disadvantage that very
136 large files on regular file systems can be fairly slow to access,
137 particularly at the end of the file, and INN incurs unnecessary
138 file system overhead when accessing the cycbuff.
139 2. Use block devices directly. If your operating system allows you to
141 call mmap() on block devices (Solaris and recent versions of Linux
142 do, FreeBSD at last report does not), this is the recommended
143 method since you can avoid all of the native file system overhead.
144 Note that some OSes do not support files larger than 2 GB, which
146 will limit the size you can make a single cycbuff, but you can
147 still combine many cycbuffs into each metacycbuff. Very old
148 versions of Linux (before 2.4 kernels, that raised the limit to
149 2 TB) are known to have this limitation; FreeBSD does not. Some
150 OSes that support large files don't support direct access to block
151 devices for large partitions (Solaris prior to Solaris 7, or not
152 running in 64-bit mode, is in this category); on those OSes, if you
153 want cycbuffs over 2 GB, you'll have to use regular files. If in
154 doubt, keep your cycbuffs smaller than 2 GB.
155 Partition the disk to make each partition equal to or smaller than
157 2 GB. If you're using Solaris, set up your partitions to avoid the
158 first cylinder of the disk (or otherwise the cycbuff header will
159 overwrite the disk partition table and render the cycbuffs
160 inaccessible). Then, create device files for each block device
161 you're going to use.
162 It's not recommended to use the block device files in /dev, since
164 the news system doesn't have permission to write to them and
165 changing the permissions of the system device files may affect
166 something else. Instead, use mknod(1) to create a new set of block
167 devices (in somewhere like pathspool/cycbuffs that's only writable
168 by the news user). To do this, run "ls -Ll" on the devices in /dev
169 that correspond to the block devices that you want to use. The
170 major and minor device numbers are in the fifth and sixth columns
171 (right before the date), respectively. Then run mknod like:
172 mknod <file> b <major> <minor>
174 where <file> is the path to the device to create (matching the
176 <file> part of the cycbuff line) and <major> and <minor> are the
177 major and minor device numbers as discovered above.
178 Here's a short script to do this when given the path to the system
180 device file as an argument:
181 #!/bin/sh
183 base=`echo "$1" | sed 's%.*/%%'`
184 major=`ls -Ll "$1" | awk '{print $5}' | tr -d ,`
185 minor=`ls -Ll "$1" | awk '{print $6}`
186 mkdir -p <pathspool in inn.conf>/cycbuffs
187 mknod <pathspool>/cycbuffs/"$base" b "$major" "$minor"
188 chown news:news <pathspool>/cycbuffs/"$base"
189 chmod 644 <pathspool>/cycbuffs/"$base"
190 Make sure that the created files are owned by the news user and
192 news group, as specified at configure time (the default being
193 "news" for both). Also make sure that the permissions on the
194 devices allow the news user to read and write, and if you want
195 other users on the system to be able to use sm to retrieve
196 articles, make sure they're world-readable.
197 Once you have everything configured properly and you start innd, you
199 should see messages in news.notice that look like:
200 innd: CNFS-sm No magic cookie found for cycbuff ONE, initializing
202 where "ONE" will be whatever you called your cycbuff.
204
206 Written by Katsuhiro Kondou <kondou@nec.co.jp> for InterNetNews.
207 Rewritten into POD by Russ Allbery <rra@stanford.edu>.
208 $Id: cycbuff.conf.pod 8987 2010-02-16 19:48:45Z iulius $
210
212 ctlinnd(8), innd(8), nnrpd(8), sm(1), storage.conf(5).
213INN 2.5.2 2010-08-11 CYCBUFF.CONF(5)