Provided by: inn2_2.5.2-1_i386 bug

NAME

       buffindexed.conf - Configuration for the buffindexed overview method

DESCRIPTION

       buffindexed.conf, found in pathetc, specifies the buffers that the
       buffindexed overview method should use.  It is required if the server
       uses buffindexed (as configured by the ovmethod parameter in inn.conf).

       Buffindexed uses pre-built buffer files to store overview data and
       indexes to that data.  The buffers are divided into 8 KB internally,
       and a given block is used either for overview data or for index data.
       A block is always allocated to a single newsgroup and is never shared
       among newsgroups.

       In addition to the buffers, buffindexed also stores information in a
       file named group.index in pathdb.  (This file should not be mistaken
       for the one named group.index in pathoverview which is used by the
       tradindexed overview method.)  It contains information about each
       newsgroup:  the pointer to the index block for the newsgroup, the high
       mark, the low mark, the flag of the group, the number of articles, and
       so forth.  This file is created automatically when all buffers are
       initialized and should not be manually edited.

       Buffindexed buffers are of fixed size, so buffindexed will never use
       more space than what is available in those buffers.  If all buffers are
       full, innd will throttle when it attempts to store overview information
       for any additional articles until space is freed (with expireover, for
       instance) or another buffer is added.  This is unlike the CNFS storage
       method.

       You can see the current usage of the buffers with the -o option to
       inndf.

       In the buffindexed.conf file, blank lines and lines beginning with a
       number sign ("#") are ignored.  All other lines must be of the format:

           <index>:<filename>:<size>

       The order of lines is not significant.

       <index> is the index of this overview buffer and must be unique.  Other
       than that constraint, it can be any number between 0 and 65535.

       <filename> is the path to the buffer.  The length of the path should
       not be longer than 63 characters.

       <size> is the length of the buffer in kilobytes (1 KB = 1024 bytes).
       If <filename> does not specify a special device, the file size of the
       buffer must be <size> * 1024 bytes.  If it does specify a special
       device, that device must have at least <size> space available.  For
       more information on setting up the buffers, see "CREATING BUFFERS".

       An example of buffindexed.conf file can be:

           0:<pathoverview in inn.conf>/OV1:1536000
           1:<pathoverview in inn.conf>/OV2:1536000

       When you first start innd with everything configured properly, you
       should see messages like this in pathlog/news.notice:

           Aug 27 00:00:00 kevlar innd: buffindexed: No magic cookie found
               for buffindexed 0, initializing

       You MUST recreate overview completely using makehistory if you remove
       or replace buffers.  However, new buffers can be added without any
       special care (other than restarting innd after modifying
       buffindexed.conf).  If you need to rebuild overview, you should zero
       all of the buffers first.

CREATING BUFFERS

       There are two methods to create a new buffindexed buffer:

       1.  Create a large file on top of a regular file system.  The easiest
           way to do this is probably with dd(1), using a command like:

               dd if=/dev/zero of=/path/to/cycbuff bs=1024 count=<size>

           where <size> is the size from the relevant line in
           buffindexed.conf.

           This is the simplest method, but has the disadvantage that very
           large files on regular file systems can be fairly slow to access,
           particularly at the end of the file, and INN incurs unnecessary
           file system overhead when accessing the buffer.

       2.  Use block devices directly.  If your operating system allows you to
           call mmap() on block devices (Solaris and recent versions of Linux
           do, FreeBSD at last report does not), this method can avoid all of
           the native file system overhead.  Note, however, that Solaris has
           problems with byte range locking on block devices, and therefore
           this method should not be used on Solaris.

           Partition the disk.  If you’re using Solaris, set up your
           partitions to avoid the first cylinder of the disk (or otherwise
           the buffindexed header will overwrite the disk partition table and
           render the buffers inaccessible).  Then, create device files for
           each block device you’re going to use.

           It’s not recommended to use the block device files in /dev, since
           the news system doesn’t have permission to write to them and
           changing the permissions of the system device files may affect
           something else.  Instead, use mknod(1) to create a new set of block
           devices (in somewhere like pathspool/overview that’s only writable
           by the news user).  To do this, run "ls -Ll" on the devices in /dev
           that correspond to the block devices that you want to use.  The
           major and minor device numbers are in the fifth and sixth columns
           (right before the date), respectively.  Then run mknod like:

               mknod <filename> b <major> <minor>

           where <filename> is the path to the device to create (matching the
           <filename> part of the buffindexed configuration line) and <major>
           and <minor> are the major and minor device numbers as discovered
           above.

           Here’s a short script to do this when given the path to the system
           device file as an argument:

               #!/bin/sh
               base=`echo "$1" | sed 's%.*/%%'`
               major=`ls -Ll "$1" | awk '{print $5}' | tr -d ,`
               minor=`ls -Ll "$1" | awk '{print $6}`
               mkdir -p <pathoverview in inn.conf>
               mknod <pathoverview>/"$base" b "$major" "$minor"
               chown news:news <pathoverview>/"$base"
               chmod 644 <pathoverview>/"$base"

           Make sure that the created files are owned by the news user and
           news group, as specified at configure time (the default being
           "news" for both).  Also make sure that the permissions on the
           devices allow the news user to read and write.

HISTORY

       Written by Katsuhiro Kondou <kondou@nec.co.jp> for InterNetNews.
       Converted to POD by Russ Allbery <rra@stanford.edu>.

       $Id: buffindexed.conf.pod 8195 2008-11-29 11:07:02Z iulius $

SEE ALSO

       expireover(8), inn.conf(5), inndf(8), makehistory(8).