Solutions

Understanding CacheFlow Restarts

Solutions ID:    KB4303
Version:    4.0
Status:    Published
Published date:    02/18/2011
Updated:    03/16/2011
 

Problem Description

There may be times when the CacheFlow appliance needs to be restarted. Restarts are required when upgrading software, during some hardware maintenance or, occasionally, to assist in troubleshooting a problem. This document describes the different types of restarts and their purposes. 

Questions answered:
  • What is the difference between cold and warm restart?
  • What is ‘restart abrupt’ and under what circumstances should it be used?

Resolution

There are five types of restart: regular (hardware or software), upgrade (hardware only) and abrupt (hardware or software).

A hardware restart shuts down the appliance and gives control to the BIOS. It is a complete hardware reset equivalent to power-cycling the appliance. During a hardware restart, the user is given the option to select an image to boot. A hardware restart is also called a cold boot.

A software restart is done completely in CacheFlow software and is much quicker than a hardware restart. Because the software is not halted, a new image cannot be loaded. A software restart is also called a warm boot.

By default, CacheFlow appliances will employ a software restart:

Blue Coat CacheFlow 5000 Series>show restart 
Restart settings
 Restart:     software only
 Core image: context only
 Compression: disabled
 
Hardware or software restart can be chosen in the restart menu at the config prompt: 
Blue Coat CacheFlow 5000 Series#(config)restart mode ?
 hardware                     Set for hardware restart
 software                     Set for software only restart
 
This setting only affects the restart regular or restart abrupt commands. Restart upgrade is always a hardware restart and cannot be modified.
 
Restart regular is the typical restart. To issue a restart regular, execute the command from the enable prompt: 
Blue Coat CacheFlow 5000 Series#restart regular
 restart regular initiated ...
Initiating a software only restart
Waiting for disk activity to cease
 
 
The other types of restarts can be invoked in the same way: 
Blue Coat CacheFlow 5000 Series#restart ?
 abrupt                       Reboot system abruptly, according to restart settings
 regular                      Reboot system according to restart settings
 upgrade                      Reboot system to start running new image
 
Restart upgrade is typically executed after a ‘load upgrade’ command, which loads a new software image and pre-selects it as the default.
 
Restart abrupt sends an interrupt to shutdown the appliance immediately. It does not wait for disk activity to end. A restart abrupt will perform a hardware or software restart depending on what the restart mode is set to. Restart abrupt essentially mimics a crash, and writes out important diagnostic information; for this reason, Blue Coat support may sometimes request a restart abrupt in order to obtain valuable information about a support case.
 
From the serial console only, the command sequence ctrl-X ctrl-C  will cause an immediate abrupt hardware restart; This sequence should only be used if other CLI sessions become non-responsive.
After a restart, the type can be determined by the message on startup. For example, a software restart:

 

 

A hardware restart will go through a full bootup including a BIOS check and an option list of available systems. Afterwards, the system restart message will be displayed:

 

These messages are also logged to syslog and can be viewed in the GUI:

 

 


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