System Administration Guide: Devices and File Systems

Swap Space as a Dump Device

A dump device is usually disk space that is reserved to store system crash dump information. By default, a system's dump device is configured to be a swap slice in a UFS root environment. If possible, you should configure an alternate disk partition as a dedicated dump device instead to provide increased reliability for crash dumps and faster reboot time after a system failure. You can configure a dedicated dump device by using the dumpadm command. For more information, see Chapter 17, Managing System Crash Information (Tasks), in System Administration Guide: Advanced Administration.

In a ZFS root environment, swap and dump are configured as separate ZFS volumes. The advantages to this model are as follows:

For more information about using ZFS swap and dump devices, see ZFS Support for Swap and Dump Devices in Solaris ZFS Administration Guide.

If you are using a volume manager to manage your disks in a UFS environment, such as Solaris Volume Manager, do not configure your dedicated dump device to be under its control. You can keep your swap areas under Solaris Volume Manager's control, which is a recommended practice. However, for accessibility and performance reasons, configure another disk as a dedicated dump device outside of Solaris Volume Manager's control.