sysdump(ADM)

Syntax

/etc/unixsyms [-n unix] [-o symsfile] [Symbols | OxValues]

Description

Whenever possible, sysdump displays a kernel stack backtrace for the input dump, together with a report of what parts have been omitted (these displays are to stderr, since stdout may be used for output). Whenever possible, sysdump uses lseek(S) to skip over blocks of zeroes, so an output regular file has ``sparse'' blocks which use no disk space. Unless dump-specific options are given, sysdump can be used to copy a file which is not a system dump to take advantage of this sparse writing.

The options for sysdump are:

-i dumpin

Specifies the location of the input dump to be copied, reduced or inspected. For example, -i /dev/swap. The input dump may already be reduced, in either -o or -O format. -i /dev/mem takes the memory image from the running system. The -i - option takes the image from the standard input but is not needed for piping from /usr/bin/compress , since sysdump can detect a compressed file (provided the default algorithm was used, not -H ) and uncompress it.

-n unix

Specifies the kernel or symbols file to be used for deciphering the input dump, and for attaching symbols to the output dump. This option is usually unnecessary, since dumpsave(ADM) uses sysdump to attach the matching symbols to the original image in /dev/swap. If unspecified, matching symbols are taken from the dump itself, or from /.unixsyms, or from the dumping kernel (if that is still available.)

-o dumpout

Specifies the location of the ouput dump, if any, to be created in deflated format; zeroed pages are not substituted for any pages omitted. This format is suitable for long-term storage on tape or disk, but cannot be understood by crash(ADM)- unless the running kernel has the dump driver configured in. The -o and -O options are mutually exclusive. The -o - option gives the dump to the standard output. For example, -o - can be used for piping to /usr/bin/compress.

-O dumpout

Specifies the location of the output dump, if any, to be created in inflated format; zeroed pages are substituted for any pages omitted. This format is always understood by crash(ADM)- unless such a dump would exceed 2Gb in size; but is unsuitable for storage except as a regular file, since only then can sparse writing avoid wasting space on the zeroed pages. The -O and -o options are mutually exclusive. The -O - option gives the dump to standard output. For example, -O - can be used for piping to /usr/bin/compress.

-a

The ``asking'' option presents a different format of report on what parts have been or could be omitted from the dump to reduce its size. If an output file has been specified, the ``asking'' option then prompts the user whether to omit each remaining part - of the kinds described below. The -a option (which prompts) and the -fumbthp options (which do not prompt) are mutually exclusive.

-f

Omits unused pages (``freemem'') from the output dump. These are seldom useful in analyzing a panic dump, and a dump can often be made much smaller by omitting them.

-u

Omits user data pages (``usermem'') from the output dump. These are seldom useful in analyzing a panic dump, and a dump can often be made much smaller by omitting them.

-m

Omits multiphysical and tape buffers (``mpbuffs'') from the output dump. These are seldom useful in analyzing a panic dump, and are often modified by the act of dumping itself; a dump can be made somewhat smaller by omitting them.

-b

Omits data blocks of the I/O buffer cache (``buffers'') from the output dump. Some may be useful in analyzing a panic dump (for example, indirect or inode blocks when analyzing a filesystem panic), but they often use a lot of space, and may be irrelevant to the panic in question.

-t

Omits process page tables (``ptables'') from the output dump. Some may be useful in analyzing a panic dump (for example, when analyzing a k_trap type E panic), but they often use a lot of space, and may be irrelevant to the panic in question. ptables cannot be omitted unless usermem is also omitted.

-h

Omits buffer cache headers (``bufhdrs'') from the output dump. These are often useful in analyzing a panic dump. So this option is not recommended, unless the bufhdrs occupy a very large amount of space, or prior analysis has proved them to be irrelevant to the panic. bufhdrs cannot be ommitted unless buffers are also omitted.

-p

Omits page frame data (``pfdata'') from the output dump. This is often useful in analyzing a panic dump. So this option is not recommended, unless pfdata occupies a very large amount of space, or prior analysis has proved it to be irrelevant to the panic. pfdata cannot be omitted unless fremem is also omitted.

The options for unixsyms are:

-n unix

Specifies the kernel whose symbol table is to be used. If unspecified, /.unixsyms is used, or the running kernel if that can be found.

-o symsfile

Specifies output symbols file to be created (or checked for update in the case of /.unixsyms). The file format is "iAPX 386 executable not stripped", but contains no executable text or data.

Symbols | 0xValues

Symbol names and/or hexademical addresses may also be specified on the command line. unixsyms then displays the hexadecimal address and symbol+offset for each.

See also

Standards conformance