Managing Systems and Workgroups: A Guide for HP-UX System Administrators

Administering a System: Managing Disks and Files
Managing Disks
Chapter 6 563
Setting Up Logical Volumes for File Systems
File systems reside in a logical volume just as they do within disk
sections or nonpartitioned disks. As of 10.10, the maximum size of HFS
and JFS (VxFS) file systems increased from 4GB to 128GB. However,
your root or boot logical volume is limited to either 2GB or 4GB,
depending on your processor. (For more information on HFS and JFS,
refer to “Determining What Type of File System to Use” on page 85.)
You can consider the space required by a file system as having three
major components, as depicted in Figure 6-3.
Figure 6-3 File System Space Components
To get a rough estimate of how big to make a logical volume which will
contain your file system, do the following:
1. Estimate how much disk space users will need for their data out into
the future. Allow for any anticipated changes which are usually in
the direction of additional growth. (Use the du command to see how
much disk space is currently being used.)
2. Add 10% to the above amount for a “minfree” area; this area is
reserved to maintain performance.
3. Add another 5% for file system overhead; this includes all data
structures required to maintain the file system.
4. Round up to the next integer multiple of the logical extent size used
in this logical volume to find the size in logical extents. (Unlike the
previous steps, this step is performed automatically for you when you
create a logical volume.)