Core Issue
When Cisco CallManager 5.x is installed, after the first reboot of the installation, the Grub loading....please wait error message appears. Then, in the next line, the Error 21 error message appears, and everything stops.The error 21 message is a generic Linux error that literally means Can not find disk.
Resolution
This might happen because the Grand Unified Bootloader (GRUB) points to a Hard Drive (HD), or the Basic Input/Output System (BIOS), that the server cannot reach.
In order to fix the problem, complete these steps:
- Make sure the server specifications are correct and Redundant Array of Independent Disks (RAID) is supported with Cisco CallManager 5.x.
- Remove the second HD, and set the RAID controller to the factory defaults.
- Rebuild the array and try the installation again.
Refer to these documents for more information:
