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vale(4) [freebsd man page]

VALE(4) 						   BSD Kernel Interfaces Manual 						   VALE(4)

NAME

     vale -- a very fast Virtual Local Ethernet using the netmap API

SYNOPSIS

     device netmap

DESCRIPTION

     vale is a feature of the netmap(4) module that implements multiple Virtual switches that can be used to interconnect netmap clients, includ-
     ing traffic sources and sinks, packet forwarders, userspace firewalls, and so on.

     vale is implemented completely in software, and is extremely fast.  On a modern machine it can move almost 20 Million packets per second
     (Mpps) per core with small frames, and about 70 Gbit/s with 1500 byte frames.

OPERATION

     vale dynamically creates switches and ports as clients connect to it using the netmap(4) API.

     vale ports are named vale[bdg:][port] where vale is the prefix indicating a VALE switch rather than a standard interface, bdg indicates a
     specific switch (the colon is a separator), and port indicates a port within the switch.  Bridge and port names are arbitrary strings, the
     only constraint being that the full name must fit within 16 characters.

     See netmap(4) for details on the API.

   LIMITS
     vale currently supports up to 4 switches, 16 ports per switch, with 1024 buffers per port.  These hard limits will be changed to sysctl vari-
     ables in future releases.

SYSCTL VARIABLES

     vale uses the following sysctl variables to control operation:

     dev.netmap.bridge	 The maximum number of packets processed internally in each iteration.	Defaults to 1024, use lower values to trade
			 latency with throughput.

     dev.netmap.verbose  Set to non-zero values to enable in-kernel diagnostics.

EXAMPLES

     Create one switch, with a traffic generator connected to one port, and a netmap-enabled tcpdump instance on another port:

	   tcpdump -ni vale-a:1 &
	   pkt-gen  -i vale-a:0 -f tx &

     Create two switches, each connected to two qemu machines on different ports.

	   qemu -net nic -net netmap,ifname=vale-1:a ... &
	   qemu -net nic -net netmap,ifname=vale-1:b ... &
	   qemu -net nic -net netmap,ifname=vale-2:c ... &
	   qemu -net nic -net netmap,ifname=vale-2:d ... &

SEE ALSO

     netmap(4)

     http://info.iet.unipi.it/~luigi/vale/

     Luigi Rizzo, Giuseppe Lettieri: VALE, a switched ethernet for virtual machines, June 2012, http://info.iet.unipi.it/~luigi/vale/

AUTHORS

     The vale switch was designed and implemented in 2012 by Luigi Rizzo and Giuseppe Lettieri at the Universita` di Pisa.

     vale was funded by the European Commission within FP7 Projects CHANGE (257422) and OPENLAB (287581).

BSD
								   July 27, 2012							       BSD

Check Out this Related Man Page

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

NAME

       expand_dump - Produces a non-compressed kernel crash dump file

SYNOPSIS

       /usr/sbin/expand_dump input-file output-file

DESCRIPTION

       By  default, kernel crash dump files (vmzcore.#) are compressed during the crash dump.  Compressed core files can be examined by the latest
       versions of debugging tools that have been recompiled to support compressed crash dump files.  However, not  all  debugging  tools  may	be
       upgraded on a given system, or you may want to examine a crash dump from a remote system using an older version of a tool.  The expand_dump
       utility produces a file that can be read by tools that have not been upgraded to support compressed crash dump files.  This  non-compressed
       version can also be read by any upgraded tool.

       This  utility  can  only  be used with compressed crash dump files, and does not support any other form of compressed file.  You cannot use
       other decompression tools such as compress, gzip, or zip on a compressed crash dump file.

       Note that the non-compressed file will require significantly more disk storage space as it is possible to achieve compression ratios of	up
       to  60:1.  Check the available disk space before running expand_dump and estimate the size of the non-compressed file as follows: Run tests
       by halting your system and forcing a crash as described in the Kernel Debugging manual.	Use an upgraded debugger to determine the value of
       the  variable  dumpsize.   Multiply this vale by the 8Kb page size to approximate the required disk space of the non-compressed crash-dump.
       Run expand_dump and pipe the output file to /dev/null, noting the size of the file that is printed when expand_dump completes its task.

RETURN VALUES

       Successful completion of the decompression.  The user did not supply the correct number of command line arguments.  The	input  file  could
       not  be	read.	The  input file is not a compressed dump, or is corrupted.  The output file could not be created or opened for writing and
       truncated.  There was some problem writing to the output file (probably a full disk).  The input file is not formated consistantly.  It	is
       probably corrupted.  The input file could not be correctly decompressed.  It is probably corrupted.

EXAMPLES

       expand_dump vmzcore.4 vmcore.4

SEE ALSO

       Commands: dbx(1), kdbx(8), ladebug(1), savecore(8)

       Kernel Debugging

       System Administration

																    expand_dump(8)
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