HP-UX Reference (11i v1 05/09) - 1M System Administration Commands A-M (vol 3)

f
fsadm_vxfs(1M) fsadm_vxfs(1M)
or deallocation activity (because fsadm acts on mounted file systems). These figures provide an indication
of fragmentation and extent availability on a file system.
Extent Reorganization
If the -e option is specified,
fsadm reorganizes the data extents on the file system whose mount point is
mount_point. The primary goal of extent reorganization is to defragment the file system.
To reduce fragmentation, extent reorganization tries to place all small files in one contiguous extent. The
-l option specifies the size of a file that is considered large. The default is 64 blocks. Extent reorganiza-
tion also tries to group large files into large extents of at least 64 blocks. Extent reorganization can
improve performance. Small files can be read or written in one I/O operation. Large files can approach
raw-disk performance for sequential I/O operations.
fsadm performs extent reorganization on all inodes on the file system. Each pass through the inodes will
move the file system closer to optimal organization.
fsadm reduces both file fragmentation and free extent fragmentation in each pass. In older versions of
VxFS, considerable effort was made to obtain an optimal file system layout. In current versions,
fsadm
relies on VxFS kernel allocation mechanisms to reallocate files in a more favorable extent geometry. At the
same time, the kernel allocation mechanism is prevented from using blocks in areas of the free list that
fsadm tries to make more contiguous.
The command syntax to perform extent reorganization is
fsadm -e [-E][-v][-s][-l
largesize][-p passes][-r rawdev][-t time] mount_point
The following example shows the output from the
fsadm -F vxfs -e -s -E
command:
# fsadm -F vxfs -e -s -E /home
Extent Fragmentation Report
Total Average Average Total
Files File Blks # Extents Free Blks
9293 115 1 149352
blocks used for indirects: 48
% Free blocks in extents smaller than 64 blks: 10.40
% Free blocks in extents smaller than 8 blks: 0.56
% blks allocated to extents 64 blks or larger: 91.67
Free Extents By Size
1: 156 2: 140 4: 101
8: 292 16: 290 32: 241
64: 155 128: 94 256: 43
512: 33 1024: 20 2048: 1
4096: 1 8192: 1 16384: 1
32768: 1 65536: 0 131072: 0
262144: 0 524288: 0 1048576: 0
2097152: 0 4194304: 0 8388608: 0
16777216: 0 33554432: 0 67108864: 0
134217728: 0 268435456: 0 536870912: 0
1073741824: 0 2147483648: 0
Pass 1 Statistics
Extents Reallocations Ioctls Errors
Searched Attempted Issued FileBusy NoSpace Total
total 12547 287 158 0 0 0
Pass 2 Statistics
Extents Reallocations Ioctls Errors
Searched Attempted Issued FileBusy NoSpace Total
total 13157 148 72 0 0 0
Extent Fragmentation Report
Total Average Average Total
Files File Blks # Extents Free Blks
9294 123 1 70400
blocks used for indirects: 64
% Free blocks in extents smaller than 64 blks: 14.00
% Free blocks in extents smaller than 8 blks: 0.70
HP-UX 11i Version 1: September 2005 − 6 − Hewlett-Packard Company Section 1M−−255