dumpfs(1m)
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dumpfs
dump DG/UX file system information
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SYNTAX
dumpfs filesys | special
DESCRIPTION
Filesys is the pathname of a directory in /etc/fstab. If this
argument is present, the device associated with that pathname
will be processed. Special is the pathname of a special file for
a device on which a file system resides.
Dumpfs lists all super-block and disk allocation region (DAR)
information for a file system. A DAR is an allocation grouping
used to distribute files over a disk. It consists of three
parts. The first two parts are of a fixed size. The first fixed
portion is the bitmap of allocated data blocks in the DAR. The
second fixed portion is the inode table for the allocation group.
The last portion of the DAR is the actual space used for the
files of the file system.
There are three sections of output by dumpfs:
1) superblock-related information
2) summary contents of the DAR entry table (DARE)
3) information for each DAR
Superblock Information
The following is printed:
* File system ID (fsid)
* minor device number
* DAR size
* number of inodes per DAR
* whether the file system is mountable
* file system name (fname)
* fpack (filesystem pack name)
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* data element size
* index element size
* directory data element size
* directory index element size
* 1st and 2nd anniversaries (facilities that control the
allocation of disk resources for each file in the
filesystem)
* number of DARs
* number of usable blocks in the file system
* actual number of blocks in file system
* number of allocated inodes
* number of free inodes
* number of data blocks
DARE Table Information
The following is printed:
* number of allocated inodes
* number of allocated data blocks
* number of directories in the DAR
DAR Information
The following is printed:
* number of allocated inodes
* number of directories in the DAR
* list of free data blocks
* number of allocated data blocks
* histogram of the free data block sizes in the DAR
When summing up the sizes of the free data blocks, the bitmap is
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dumpfs(1m)
scanned starting with the bits representing the data area. The
file system block allocation algorithms do not count any sequence
of ``data element size'' free bits in the bitmap as a free data
element. Contiguous data blocks will only be allocated as a data
element if the sequence of bits in the bitmap are aligned on a
``data element size'' boundary. For example, if the data element
size of the file system is 16 blocks, a data element will only be
allocated if a sequence of 16 free bits in the bitmap are aligned
on a 16-bit (word) boundary in the bitmap. This holds true for
data element sizes up to 32 blocks, but any data element size
greater than 32 blocks will search starting on any 32-bit (long
word) boundary.
SEE ALSO
fsck(1m), mkfs(1m), tunefs(1m), fs(4), fstab(4).
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