Solaris 10 Installation Guide: Network-Based Installations

General Disk Space Planning and Recommendations

Planning disk space is different for everyone. Consider allocating space for the following conditions, depending on your needs.

Table 3–5 General Disk Space and Swap Space Planning

Conditions for Space Allocations 


File systems 

For each file system that you create, allocate an additional 30 percent more disk space than you need to enable you to upgrade to future Solaris versions.  

By default, the Solaris installation methods create only root (/) and /swap. When space is allocated for OS services, the /export directory is also created. If you are upgrading to a major Solaris release, you might need to reslice your system or allocate double the space that you need at installation time. If you are upgrading to an update, you could prevent having to reslice your system by allocating extra disk space for future upgrades. A Solaris update release needs approximately 10 percent more disk space than the previous release. You can allocate an additional 30 percent of disk space for each file system to allow space for several Solaris updates.

The /var file system

If you intend to use the crash dump feature savecore(1M), allocate double the amount of your physical memory in the /var file system.


The Solaris installation program allocates a default swap area of 512 Mbytes under the following conditions: 

  • If you use the installation program's automatic layout of disk slices

  • If you avoid manually changing the size of the swap slice

By default, the Solaris installation programs allocate swap space by placing swap so that it starts at the first available disk cylinder (typically cylinder 0 on SPARC based systems). This placement provides maximum space for the root (/) file system during the default disk layout and enables the growth of the root (/) file system during an upgrade.

If you think you might need to expand the swap area in the future, you can place the swap slice so that it starts at another disk cylinder by using one of the following methods.  

For an overview of the swap space, see Chapter 21, Configuring Additional Swap Space (Tasks), in System Administration Guide: Devices and File Systems.

A server that is providing home directory file systems 

By default, home directories are usually located in the /export file system.

The Solaris software group you are installing 

A software group is a grouping of software packages. When you are planning disk space, remember that you can add or remove individual software packages from the software group that you select. For information about software groups, see Disk Space Recommendations for Software Groups.


Language support 

For example, Chinese, Japanese, or Korean. If you plan to install a single language, allocate approximately 0.7 Gbytes of additional disk space for the language. If you plan to install all language supports, you need to allocate up to approximately 2.5 Gbytes of additional disk space for the language supports, depending on the software group you install. 

Printing or mail support 

Allocate additional space. 

Additional software or third-party software 

Allocate additional space.