How Disaster Recovery Using a Hard Disk Recovery Partition Works
This new method of disaster recovery introduced from Cisco IOS XR Release 5.2.5 onwards helps overcome operational delays that may occur when a router is in a non-responding state.
Typically, when the router is in a non-responsive state, the administrator has to physically access the router and then take corrective action. Inability to quickly access the router can lead to delays in recovering the router and subsequently cause extended downtime in router operations. To overcome this constraint, this new method of disaster recovery can be performed remotely.
In this method of disaster recovery, while the router is in operational state, a recovery image is copied to a hard disk recovery partition in the RP (route processor) and SC (shelf controller) card. The administrator remotely accesses this recovery image to restore a router.
When the system is in a state of disaster, recovery can be performed only if the following conditions are met:
- The primary BIOS on all RP or SC cards is of version 14.07.
- A hard disk recovery partition already exists on a RP and SC card hard disk with the desired recovery image content.
The following figure illustrates the process of getting a system ready for recovery.
Performing disaster recovery by using a hard disk partition involves the following:
Preparing the Router for Disaster Recovery
Preparing the router for disaster recovery involves copying the recovery image to a hard disk recovery partition when the router is in a fully functional state. To prepare a router for disaster recovery, execute the following steps:
Before you begin
Download the compressed recovery image from software download page at cisco.com to the hard disk of the router. The filename for the compressed boot file is in this format: ncs6k-dr-boot.tar-release_number. For example, ncs6k-dr-boot.tar-5.2.5
Ensure that the version of primary BIOS on all the RP and SC cards is of version 14.07. If the primary BIOS is of a lower version, use the upgrade hw-module location location fpd Primary-BIOS command.
If you are performing disaster recovery in a multi-chassis environment ensure that there is control ethernet connectivity between the chassis before you boot an RP or SC card from the hard disk recovery partition.
- install verify packages location node-id
- show install log install-id
- install backup node-id location destination
install verify packages location node-id
Use this command to verify if a partition with a recovery image exists.
show install log install-id
If a hard disk partition already exists, similar output is displayed:
If a hard disk partition does not exist, similar output is displayed:
install backup node-id location destination
Creates a hard disk partition and copies the recovery image to the hard disk of the RP and SC card. If a partition already exists, the recovery image is updated.
The following example shows the contents of the log file after install backup command is executed.
What to do next
After the router is prepared for disaster recovery, you can recover the router by the recovery image stored in the hard disk recovery partition. For details on recovering the router when it is in a non-responding state, see Recovering a Router
Recovering a Router
If the router is in a non-responding state, it can be restored by using a recovery image that is stored in the hard disk recovery partition of the router. Sometimes, even if the router is in a non-responding state, the command-line interface will respond and can be used to execute commands to recover the router. Determine the state of the command-line interface and execute the steps based on the requirement.
The router can be recovered using the following method:
Recovering a Router Using Boot Manager
Use this method of recovery if the router is in a non-responding state and the command line interface is not functional.
Before you begin
Ensure that you have prepared the router for disaster recovery by using the information in Preparing the Router for Disaster Recovery
Power cycle the router.
Press F12 to go to the Boot Manager and select Recovery Host OS