Displays the placement of file blocks within logical or physical volumes.
fileplace [{ -l | -p [-o FragOffset] [ -n FragNumber] }[ -i ] [ -v ]] File | [-m LogicalVolumeName]
The fileplace command displays the placement of a specified file within the logical or physical volumes containing the file.
By default, the fileplace command lists to standard output the ranges of logical volume fragments allocated to the specified file. The order in which the logical volume fragments are listed corresponds directly to their order in the file. A short header indicates the file size (in bytes), the name of the logical volume in which the file lies, the block size (in bytes) for that volume, the fragment size in bytes, and the compression, indicating if the file system is compressed or not.
Occasionally, portions of a file may not be mapped to any fragments in the volume. These areas, whose size is an integral number of fragments, are implicitly zero-filled by the file system. The fileplace command indicates which areas in a file have no allocated fragments.
Optionally, the fileplace command also displays:
These limits apply only to a single extent; in no way do they have any limiting effects on overall file sizes.
Item | Description |
---|---|
-i | Displays the indirect blocks for the file, if any. The indirect blocks are displayed in terms of either their logical or physical volume block addresses, depending on whether the -l or -p flag is specified. |
-l | Displays file placement in terms of logical
volume fragments,
for the logical volume containing the file. The -l and -p flags are mutually exclusive. Note: If neither the -l flag nor the-p flag is specified, the -l flag is implied by default. If both flags are specified, the -p flag is used. |
-m LogicalVolumeName | Displays the logical to physical map for a logical volume. |
-n FragNumber | Displays the logical or physical file blocks ranging from the first block to the block corresponding to FragNumber. |
-o FragOffset | Displays the logical or physical file blocks ranging from the block corresponding to fragoffset + 1 to the last block. The fileplace command displays the address of the specific fragment when both the -n flag and the -o flag is specified. |
-p | Displays file placement in terms of underlying physical volume, for the physical volumes that contain the file. If the logical volume containing the file is mirrored, the physical placement is displayed for each mirror copy. The -l and -p flags are mutually exclusive. |
-v | Displays more information about the file and its placement,
including statistics on how widely the file is spread across the volume
and the degree of fragmentation in the volume. The statistics are
expressed in terms of either the logical or physical volume fragment
numbers, depending on whether the -l or -p flag is specified.
File space efficiency is calculated as the number of nonnull fragments (N) divided by the range of fragments (R) assigned to the file and multiplied by 100, or (N /R) x 100. Range is calculated as the highest assigned address minus the lowest assigned address plus 1, or MaxBlk-MinBlk+1. For example, the logical blocks written for the file are 01550 through 01557, so N equals 8. The range, R, (01557 - 01550 +1) also equals 8. Space efficiency for this file is 100% or 8/8 x 100. The -v flag message prints the results of the (N/R)+100 equation. According to this method of calculating efficiency, files greater than 32KB are never 100% efficient because of their use of the indirect block. Sequential efficiency is defined as 1 minus the number of gaps (nG) divided by number of possible gaps (nPG) or 1 - (nG/nPG). The number of possible gaps equals N minus 1 ( nPG=N - 1). If the file is written to 9 blocks (greater than 32KB), and the logical fragment column shows:
The file is stored in 2 fragments out of a possible 9 fragments. The sequential efficiency calculation for this file is:
|
fileplace data1
This example displays
the list of fragments and the logical volume that contains the file data1.fileplace -i data1
In addition
to the default list of
logical volume fragments, the indirect blocks (if any) used to store
the file block addresses in the file system are enumerated. fileplace -v data1
In addition to the default
list of logical volume fragments, statistics about the placement efficiency
are displayed. fileplace -piv data1
This example displays the list of file and indirect blocks in terms
of the underlying physical volumes, and includes statistics about
the efficiency of the placement. fileplace -n 18 -p /usr/lib/boot/unix_mp
fileplace -p -o 17 /usr/lib/boot/unix_mp
fileplace -o 17 -n 1 -p /usr/lib/boot/unix_mp
Item | Description |
---|---|
/dev/hd0, /dev/hd1, .../dev/hdn | Specifies the logical volume. |