Displays the placement of file blocks within logical or physical volumes.
fileplace [ { -l | -p } [ -i ] [ -v ] ] File
The fileplace command displays the placement of a specified file within the AIX 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 will indicate which areas in a file have no allocated fragments.
Optionally, the fileplace command will also display:
Notes:
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.
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:
01550-01557 01600
The file is stored in 2 fragments out of a possible 9 fragments. The sequential efficiency calculation for this file is:
fileplace data1This example displays the list of fragments and the logical volume that contains the file data1 .
fileplace -i data1In 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 data1In addition to the default list of logical volume fragments, statistics about the placement efficiency are displayed.
fileplace -piv data1This 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.
The sync command.
Monitoring and Tuning Disk I/O in AIX Versions 3.2 and 4 Performance Tuning Guide
The Logical Volume Storage Overview in AIX Version 4 System Management Guide: Operating System and Devices defines and discusses logical volume storage.