Red Hat ENTERPRISE LINUX 5 - VIRTUALIZATION GUIDE Manual page 6

Virtualization Guide
VII. Tips and Tricks
31. Tips and tricks
31.1. Automatically starting guests ........................................................................... 321
31.2. Changing between the KVM and Xen hypervisors ............................................. 321
31.2.1. Xen to KVM ......................................................................................... 321
31.2.2. KVM to Xen ......................................................................................... 323
31.3. Using qemu-img ............................................................................................. 324
31.4. Overcommitting with KVM ............................................................................... 325
31.5. Modifying /etc/grub.conf ................................................................................... 327
31.6. Verifying virtualization extensions ..................................................................... 328
31.7. Accessing data from a guest disk image .......................................................... 329
31.8. Setting KVM processor affinities ...................................................................... 331
31.9. Identifying guest type and implementation ........................................................ 335
31.10. Generating a new unique MAC address ......................................................... 336
31.11. Limit network bandwidth for a Xen guest ........................................................ 337
31.12. Configuring Xen processor affinities ............................................................... 338
31.13. Modifying the Xen hypervisor ......................................................................... 338
31.14. Very Secure ftpd ........................................................................................ 339
31.15. Configuring LUN Persistence ......................................................................... 339
31.16. Disable SMART disk monitoring for guests ..................................................... 341
31.17. Cleaning up old Xen configuration files ........................................................... 341
31.18. Configuring a VNC Server ............................................................................. 341
31.19. Cloning guest configuration files .................................................................... 342
31.20. Duplicating an existing guest and its configuration file ..................................... 342
32. Creating custom libvirt scripts
32.1. Using XML configuration files with virsh ........................................................... 345
VIII. Troubleshooting
33. Troubleshooting Xen
33.1. Debugging and troubleshooting Xen ................................................................ 349
33.2. Log files overview ........................................................................................... 350
33.3. Log file descriptions ........................................................................................ 351
33.4. Important directory locations ............................................................................ 351
33.5. Troubleshooting with the logs .......................................................................... 352
33.6. Troubleshooting with the serial console ............................................................ 352
33.7. Para-virtualized guest console access .............................................................. 353
33.8. Fully virtualized guest console access .............................................................. 353
33.9. Common Xen problems .................................................................................. 353
33.10. Guest creation errors .................................................................................... 354
33.11. Troubleshooting with serial consoles .............................................................. 354
33.11.1. Serial console output for Xen .............................................................. 354
33.11.2. Xen serial console output from para-virtualized guests .......................... 355
33.11.3. Serial console output from fully virtualized guests ................................. 356
33.12. Xen configuration files ................................................................................... 356
33.13. Interpreting Xen error messages .................................................................... 357
33.14. The layout of the log directories ..................................................................... 360
34. Troubleshooting
34.1. Identifying available storage and partitions ....................................................... 361
34.2. After rebooting Xen-based guests the console freezes ...................................... 361
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