STORAGE.CONF(5) InterNetNews Documentation STORAGE.CONF(5)NAMEstorage.conf - Configuration file for storage manager
DESCRIPTION
The file pathetc/storage.conf contains the rules to be used in
assigning articles to different storage methods. These rules determine
where incoming articles will be stored.
The storage manager is a unified interface between INN and a variety of
different storage methods, allowing the news administrator to choose
between different storage methods with different trade-offs (or even
use several at the same time for different newsgroups, or articles of
different sizes). The rest of INN need not care what type of storage
method was used for a given article; the storage manager will figure
this out automatically when that article is retrieved via the storage
API. Note that you may also want to see the options provided in
inn.conf(5) regarding article storage.
The storage.conf file consists of a series of storage method entries.
Blank lines and lines beginning with a number sign ("#") are ignored.
The maximum number of characters in each line is 255. The order of
entries in this file is important, see below.
Each entry specifies a storage method and a set of rules. Articles
which match all of the rules of a storage method entry will be stored
using that storage method; if an article matches multiple storage
method entries, the first one will be used. Each entry is formatted as
follows:
method <methodname> {
class: <storage_class>
newsgroups: <wildmat>
size: <minsize>[,<maxsize>]
expires: <mintime>[,<maxtime>]
options: <options>
exactmatch: <bool>
}
If spaces or tabs are included in a value, that value must be enclosed
in double quotes (""). If either a number sign ("#") or a double quote
are meant to be included verbatim in a value, they should be escaped
with "\".
<methodname> is the name of a storage method to use for articles which
match the rules of this entry. The currently available storage methods
are:
cnfs
timecaf
timehash
tradspool
trash
See the "STORAGE METHODS" section below for more details.
The meanings of the keys in each storage method entry are as follows:
class: <storage_class>
An identifier for this storage method entry. <storage_class>
should be a number between 0 and 255. It should be unique across
all of the entries in this file. It is mainly used for specifying
expiration times by storage class as described in expire.ctl(5);
"timehash" and "timecaf" will also set the top-level directory in
which articles accepted by this storage class are stored. The
assignment of a particular number to a storage class is arbitrary
but permanent (since it is used in storage tokens). Storage
classes can be for instance numbered sequentially in storage.conf.
newsgroups: <wildmat>
What newsgroups are stored using this storage method. <wildmat> is
a uwildmat(3) pattern which is matched against the newsgroups an
article is posted to. If storeonxref in inn.conf is true, this
pattern will be matched against the newsgroup names in the Xref:
header; otherwise, it will be matched against the newsgroup names
in the Newsgroups: header (see inn.conf(5) for discussion of the
differences between these possibilities). Poison wildmat
expressions (expressions starting with "@") are allowed and can be
used to exclude certain group patterns: articles crossposted to
poisoned newsgroups will not be stored using this storage method.
The <wildmat> pattern is matched in order.
There is no default newsgroups pattern; if an entry should match
all newsgroups, use an explicit "newsgroups: *".
size: <minsize>[,<maxsize>]
A range of article sizes (in bytes) which should be stored using
this storage method. If <maxsize> is 0 or not given, the upper
size of articles is limited only by maxartsize in inn.conf. The
size: field is optional and may be omitted entirely if you want
articles of any size to be stored in this storage method (if, of
course, these articles fulfill all the other requirements of this
storage method entry). By default, <minsize> is set to 0.
expires: <mintime>[,<maxtime>]
A range of article expiration times which should be stored using
this storage method. Be careful; this is less useful than it may
appear at first. This is based only on the Expires: header of the
article, not on any local expiration policies or anything in
expire.ctl! If <mintime> is non-zero, then this entry will not
match any article without an Expires: header. This key is
therefore only really useful for assigning articles with requested
longer expire times to a separate storage method. Articles only
match if the time until expiration (that is to say, the amount of
time into the future that the Expires: header of the article
requests that it remain around) falls in the interval specified by
<mintime> and <maxtime>.
The format of these parameters is "0d0h0m0s" (days, hours, minutes,
and seconds into the future). If <maxtime> is "0s" or is not
specified, there is no upper bound on expire times falling into
this entry (note that this key has no effect on when the article
will actually be expired, but only on whether or not the article
will be stored using this storage method). This field is also
optional and may be omitted entirely if you do not want to store
articles according to their Expires: header, if any.
A <mintime> value greater than "0s" implies that this storage
method won't match any article without an Expires: header.
options: <options>
This key is for passing special options to storage methods that
require them (currently only "cnfs"). See the "STORAGE METHODS"
section below for a description of its use.
exactmatch: <bool>
If this key is set to true, all the newsgroups in the Newsgroups:
header of incoming articles will be examined to see if they match
newsgroups patterns. (Normally, any non-zero number of matching
newsgroups is sufficient, provided no newsgroup matches a poison
wildmat as described above.) This is a boolean value; "true",
"yes" and "on" are usable to enable this key. The case of these
values is not significant. The default is false.
If an article matches all of the constraints of an entry, it is stored
via that storage method and is associated with that <storage_class>.
This file is scanned in order and the first matching entry is used to
store the article.
If an article does not match any entry, either by being posted to a
newsgroup which does not match any of the <wildmat> patterns or by
being outside the size and expires ranges of all entries whose
newsgroups pattern it does match, the article is not stored and is
rejected by innd. When this happens, the error message:
cant store article: no matching entry in storage.conf
is logged to syslog. If you want to silently drop articles matching
certain newsgroup patterns or size or expires ranges, assign them to
the "trash" storage method rather than having them not match any
storage method entry.
STORAGE METHODS
Currently, there are five storage methods available. Each method has
its pros and cons; you can choose any mixture of them as is suitable
for your environment. Note that each method has an attribute
EXPENSIVESTAT which indicates whether checking the existence of an
article is expensive or not. This is used to run expireover(8).
cnfs
The "cnfs" storage method stores articles in large cyclic buffers
(CNFS stands for Cyclic News File System). Articles are stored in
CNFS buffers in arrival order, and when the buffer fills, it wraps
around to the beginning and stores new articles over the top of the
oldest articles in the buffer. The expire time of articles stored
in CNFS buffers is therefore entirely determined by how long it
takes the buffer to wrap around, which depends on how quickly data
is being stored in it. (This method is therefore said to have
self-expire functionality.) EXPENSIVESTAT is false for this
method.
CNFS has its own configuration file, cycbuff.conf, which describes
some subtleties to the basic description given above. Storage
method entries for the "cnfs" storage method must have an options:
field specifying the metacycbuff into which articles matching that
entry should be stored; see cycbuff.conf(5) for details on
metacycbuffs.
Advantages: By far the fastest of all storage methods (except for
"trash"), since it eliminates the overhead of dealing with a file
system and creating new files. Unlike all other storage methods,
it does not require manual article expiration. With CNFS, the
server will never throttle itself due to a full spool disk, and
groups are restricted to just the buffer files given so that they
can never use more than the amount of disk space allocated to them.
Disadvantages: Article retention times are more difficult to
control because old articles are overwritten automatically.
Attacks on Usenet, such as flooding or massive amounts of spam, can
result in wanted articles expiring much faster than intended (with
no warning).
timecaf
This method stores multiple articles in one file, whose name is
based on the article's arrival time and the storage class. The
file name will be:
<patharticles>/timecaf-nn/bb/aacc.CF
where "nn" is the hexadecimal value of <storage_class>, "bb" and
"aacc" are the hexadecimal components of the arrival time, and "CF"
is a hardcoded extension. (The arrival time, in seconds since the
epoch, is converted to hexadecimal and interpreted as 0xaabbccdd,
with "aa", "bb", and "cc" used to build the path.) This method
does not have self-expire functionality (meaning expire has to run
periodically to delete old articles). EXPENSIVESTAT is false for
this method.
Advantages: It is roughly four times faster than "timehash" for
article writes, since much of the file system overhead is bypassed,
while still retaining the same fine control over article retention
time.
Disadvantages: Using this method means giving up all but the most
careful manually fiddling with the article spool; in this aspect,
it looks like "cnfs". As one of the newer and least widely used
storage types, "timecaf" has not been as thoroughly tested as the
other methods.
timehash
This method is very similar to "timecaf" except that each article
is stored in a separate file. The name of the file for a given
article will be:
<patharticles>/time-nn/bb/cc/yyyy-aadd
where "nn" is the hexadecimal value of <storage_class>, "yyyy" is a
hexadecimal sequence number, and "bb", "cc", and "aadd" are
components of the arrival time in hexadecimal (the arrival time is
interpreted as documented above under "timecaf"). This method does
not have self-expire functionality. EXPENSIVESTAT is true for this
method.
Advantages: Heavy traffic groups do not cause bottlenecks, and a
fine control of article retention time is still possible.
Disadvantages: The ability to easily find all articles in a given
newsgroup and manually fiddle with the article spool is lost, and
INN still suffers from speed degradation due to file system
overhead (creating and deleting individual files is a slow
operation).
tradspool
Traditional spool, or "tradspool", is the traditional news article
storage format. Each article is stored in an individual text file
named:
<patharticles>/news/group/name/nnnnn
where "news/group/name" is the name of the newsgroup to which the
article was posted with each period changed to a slash, and "nnnnn"
is the sequence number of the article in that newsgroup. For
crossposted articles, the article is linked into each newsgroup to
which it is crossposted (using either hard or symbolic links).
This is the way versions of INN prior to 2.0 stored all articles,
as well as being the article storage format used by C News and
earlier news systems. This method does not have self-expire
functionality. EXPENSIVESTAT is true for this method.
Advantages: It is widely used and well-understood; it can read
article spools written by older versions of INN and it is
compatible with all third-party INN add-ons. This storage
mechanism provides easy and direct access to the articles stored on
the server and makes writing programs that fiddle with the news
spool very easy, and gives fine control over article retention
times.
Disadvantages: It takes a very fast file system and I/O system to
keep up with current Usenet traffic volumes due to file system
overhead. Groups with heavy traffic tend to create a bottleneck
because of inefficiencies in storing large numbers of article files
in a single directory. It requires a nightly expire program to
delete old articles out of the news spool, a process that can slow
down the server for several hours or more.
trash
This method silently discards all articles stored in it. Its only
real uses are for testing and for silently discarding articles
matching a particular storage method entry (for whatever reason).
Articles stored in this method take up no disk space and can never
be retrieved, so this method has self-expire functionality of a
sort. EXPENSIVESTAT is false for this method.
EXAMPLES
The following sample storage.conf file would store all articles posted
to alt.binaries.* in the "BINARIES" CNFS metacycbuff, all articles over
roughly 50 KB in any other hierarchy in the "LARGE" CNFS metacycbuff,
all other articles in alt.* in one timehash class, and all other
articles in any newsgroups in a second timehash class, except for the
internal.* hierarchy which is stored in traditional spool format.
method tradspool {
class: 1
newsgroups: internal.*
}
method cnfs {
class: 2
newsgroups: alt.binaries.*
options: BINARIES
}
method cnfs {
class: 3
newsgroups: *
size: 50000
options: LARGE
}
method timehash {
class: 4
newsgroups: alt.*
}
method timehash {
class: 5
newsgroups: *
}
Notice that the last storage method entry will catch everything. This
is a good habit to get into; make sure that you have at least one
catch-all entry just in case something you did not expect falls through
the cracks. Notice also that the special rule for the internal.*
hierarchy is first, so it will catch even articles crossposted to
alt.binaries.* or over 50 KB in size.
As for poison wildmat expressions, if you have for instance an article
crossposted between misc.foo and misc.bar, the pattern:
misc.*,!misc.bar
will match that article whereas the pattern:
misc.*,@misc.bar
will not match that article. An article posted only to misc.bar will
fail to match either pattern.
Usually, high-volume groups and groups whose articles do not need to be
kept around very long (binaries groups, *.jobs*, news.lists.filters,
etc.) are stored in CNFS buffers. Use the other methods (or CNFS
buffers again) for everything else. However, it is as often as not
most convenient to keep in "tradspool" special hierarchies like local
hierarchies and hierarchies that should never expire or through the
spool of which you need to go manually.
HISTORY
Written by Katsuhiro Kondou <kondou@nec.co.jp> for InterNetNews.
Rewritten into POD by Julien Elie.
$Id: storage.conf.pod 8357 2009-02-27 17:56:00Z iulius $
SEE ALSOcycbuff.conf(5), expire.ctl(5), expireover(8), inn.conf(5), innd(8),
uwildmat(3).
INN 2.5.3 2009-05-21 STORAGE.CONF(5)
