HP-UX Reference (11i v2 03/08) - 1M System Administration Commands A-M (vol 3)

f
fsdb_vxfs(1M) fsdb_vxfs(1M)
NAME
fsdb_vxfs: fsdb - VxFS file system debugger
SYNOPSIS
fsdb [-F vxfs][-z
inumber] special
DESCRIPTION
fsdb can analyze VxFS file system problems or repair a damaged VxFS file system after a crash. A spe-
cial device special specifies the file system to debug. The
fsdb command is intended for experienced
users only.
fsdb can convert block and inumbers into their corresponding disk addresses. In addition, mnemonic
offsets allow access to different parts of an inode. These greatly simplify the process of correcting control
block entries or descending the file system tree.
By default, numbers are considered decimal. You must prefix octal numbers with
0, and prefix hexade-
cimal numbers with
0x. When using hexadecimal numbers, it is preferable to follow the number with a
space, because several commands are letters that are also hexadecimal digits. In this document a pound
sign (#) indicates that a number is to be specified.
fsdb reads a block at a time and works with raw and block I/O. All I/O is unbuffered, so changes made
to the file system are immediate and changes made by other processes or by the kernel are immediately
seen by fsdb.
Options
fsdb recognizes the following options:
generic_options Supported by the generic
fsdb command. See fsdb(1M).
-F vxfs Specify the VxFS file-system type.
-z inumber Clear the inode identified by inumber (non-interactive). Multiple
-z options accu-
mulate.
Operands
fsdb recognizes the following operand:
special Name of the special device that contains the VxFS file system to debug.
Using Commands and Symbols
It is best to separate each token on a command line with a space. Although the command parser does not
require element separation, there is no ambiguity in the command language if each token is separated
with a space. For example, the command 0x23b b sets the current position to block 0x23b hexade-
cimal. The command 0x23bb is invalid, because the command is parsed as simply a hexadecimal
number. The command 23b positions to block 23 decimal, since the command is not ambiguous.
You can separate commands with new lines. You can put multiple commands on one line and separate
them with a dot (
.) or a semicolon (;) If multiple commands are placed on one line, generally only the
last command displays results. This allows positioning commands to be followed by printing commands
or change commands without intermediate printing.
Symbols for the fsdb Command
The following symbols are recognized by the
fsdb command:
h[mod|print]
Print summary of commands that display [modify|format] the file system.
?[mod|print]
Print summary of commands that display [modify|format] the file system.
help[mod|print]
Print summary of commands that display [modify|format] the file system.
! Escape to shell.
| Pipe output of fsdb to a shell command.
q Quit.
string A character string. Inside a character string, a NULL character can be specified
with ‘‘\0’’; a double quote can be specified with ‘‘\"’’; and a backslash can be
Section 1M−−230 Hewlett-Packard Company − 1 − HP-UX 11i Version 2: August 2003