HP-UX Reference (11i v2 07/12) - 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 special
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 accumu-
late.
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 hexadecimal. The
command 0x23bb is invalid, because the command is parsed as simply a hexadecimal number. The com-
mand 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.
HP-UX 11i Version 2: December 2007 Update − 1 − Hewlett-Packard Company 299