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DSPOOLOUT(8)		    System Manager's Manual		  DSPOOLOUT(8)

NAME
       dspoolout - Diablo program to sequence and flush	outbound queue files

SYNOPSIS
       dspoolout [ -q ]	[ -v ] [ -n ] [	-s minutes ] [ -m maxrun ] [ -T	txbuf-
       size ] [	-R rxbufsize ] [ -B ip ] [ -f configfile ] [ label ]

DESCRIPTION
       DSpoolout reads the dnntpspool.ctl file and applies a  sequence	number
       to  the	outbound queue files maintained	by diablo in the dqueue	direc-
       tory.  This involves renaming each queue	file then running a  dicmd  to
       flush  them.  DSpoolout is normally run from cron once every 5 minutes.
       The control file	tells DSpoolout	how many queue files to	 maintain  for
       any given outbound feed and how many dnewslink processes	to run in par-
       allel for each outbound feed.  The default is 2,	and may	be changed  by
       the  -m maxrun option.  The dnewslink program itself is able to process
       multiple	queue files in sequence, and judicious use of flock() prevents
       collisions  when	 multiple  processes  are run on the same range	of se-
       quence numbers.	DSpoolout manages the  whole  affair.	DSpoolout  can
       also  run  smart	based on whether the feeds are able to stay caught up.
       The -s minutes option tells DSpoolout how often to sequence out	a  new
       outbound	queue file and (potentially) run more dnewslinks when the feed
       is unable to stay caught	up with	our queue files.  If the feed is  able
       to stay caught up, the option is	ignored	and DSpoolout attempts to han-
       dle the feed every time it is run.  This	allows you to reduce  the  re-
       queueing	 latency  between  incoming and	outgoing feeds for those feeds
       able to handle your article rate	without	overloading the	 machine  when
       you have	many feeds.

       The  -B	option	causes	DSpoolout  to pass the specified IP address to
       dnewslink, specifying the local address to be  used  for	 all  outbound
       NNTP sessions.

       The  -n	option	causes	dspoolout  to flush and	rotate the queue files
       without executing any dnewslink's.

       An optional queue label may be specified	to restrict dspoolout's	opera-
       tion to a single	entry.	Otherwise, all entries are run.

       -f  configfile  Specify	a configuration	file other then	dspoolout.ctl.
       If the configuration file is not	an absolute path, diablo's  news  home
       is prepended to it.

       The  -T and -R options set the transmit and receive TCP buffer size for
       dnewslink.  The defaults	are usually ok,	but if you want	to  be	frugal
       you  can	usually	reduce the receive buffer size without blowing the ef-
       ficiency.

       It is suggested,	however, that you run DSpoolout	from cron no more then
       once  every  5 minutes.	Heavy backbone transit points with lots	of cpu
       cycles can get away with	running	DSpoolout every	2 minutes if they  re-
       ally  want  to,	in  which case the -s option really comes in handy.  A
       typical news path of 8 elements will propogate in 5x8 = 40 minutes with
       a 5 minute queue	run, and 16 minutes with a 2 minute queue run.

       Many people proscribe real-time feeds.  Diablo tries to avoid real-time
       feeds for two reasons:  First, they add complexity to the  main	server
       and  the	additional system calls	slow it	down.  Second, real time feeds
       can lead	to a false sense of security and efficiency.  While it is true
       that  a	real-time  feed	 will make better use of the kernel file cache
       then a queued feed, very	few news servers can dependably	rely  on  this
       to maintain their feed rates... they MUST be designed to	handle article
       delays and failures.  A server running too close	to the edge will expe-
       rience  a  NASTY	 cascade failure if it relies on the efficiency	of the
       real time feed to maintain the article feed rate.

REALTIME FEEDS
       DSpoolout is capable of maintaining a dnewslink on designated  realtime
       feeds.	A  feed	is specified as	being realtime by using	the 'realtime'
       option in the dnntpspool.ctl file (see the sample dnntpspool.ctl	file).
       This  is	really only a near-real-time capability, since Diablo buffer's
       writes to outgoing queue	files.	For a nominal full feed, the delay  is
       approximately 5 seconds.

       The  way	it works is as follows:	 dspoolout starts a dnewslink with the
       -r option on the	active outgoing	feed file.   DSpoolout	also  operates
       normally, attempting to start dnewslinks	on any existing	queue files up
       to a specified limit.  When dspoolout is	next run, it flushes  and  ro-
       tates  as per normal.  The dnewslink -r sitting on the active file will
       get  it	renamed	 out  from  under.   It	 detects  this	condition  and
       closes/reopens  the  new	active file as well as aattempts to remove the
       old one if it has finished processing it	and no errors occured.

SEE ALSO
       diablo(8), dicmd(8), didump(8), diload(8), dnewslink(8),	doutq(8), dex-
       pire(8),	  dexpireover(8),  diconvhist(8),  dilookup(8),	 dspoolout(8),
       dkp(8), dpath(8), diablo-kp(5), diablo-files(5)

								  DSPOOLOUT(8)

NAME | SYNOPSIS | DESCRIPTION | REALTIME FEEDS | SEE ALSO

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