Tools for XenServer Troubleshooting: http://blogs.citrix.com/2011/05/06/tools-for-xenserver-troubleshooting/

How to Collect Diagnostic Information for XenServer: http://support.citrix.com/article/CTX125372

Helpful XenServer Commands: http://support.randomsolutions.nl/432213-Helpfull-XenServer-Commands

Try booting with the 'Fallback' kernel and look for clues in the boot messages.

Type fallback or fallback-serial at the boot: prompt.

See also RAID Metadata Removal

If you are installing to disks that previously had been used in RAID configurations, you may get a kernel panic (hang on boot).

You probably won't see the kernel panic (hang on boot) until after installing SP1 (XenServer 6.2).

df -h | grep "/$" | head -n 1

Looking for files bigger than a given size (specify path and size):

find / -mount -type f -size +20M -exec ls -lh {} \; | awk '{ print $9 ": " $5 }'

You can pretty much ignore anything in /var/run/sr-mount/ as it's not on the local filesystem.

Take special care when using wildcards with the rm command!

The first step might be to delete all files such as downloaded patches from /root:

ls -al /root
rm -rf /root/*

https://support.citrix.com/article/CTX202821

http://xenserver.org/component/easyblog/entry/xenserver-root-disk-maintenance.html?Itemid=179

List out the VBD (connector object between VM and VDI) based on the VDI UUID:

xe vdi-list | grep -B1 -A5 -i "part-of-vm-name"

xe vdi-list name-label="<VDI-name-label>"

xe vbd-list vdi-uuid=<UUID of VDI>

Once done, you want to first try to make VBD inactive (it may already be inactive),

xe vbd-unplug uuid=<UUID of VBD>

Once done, you can then break the connection:

xe vbd-destroy uuid=<UUID of VBD>

Check in XenCenter to verify and delete the virtual disk.

Delete rotated log files:

find /var/log/ -type f -name *.gz -exec rm -f {} \;

Delete tapdisk log files:

rm -f /var/log/blktap/*

Delete applied patches:

Works pool-wide if run on the pool master server.

for i in `xe patch-list --minimal|tr "," " "`;do xe patch-pool-clean uuid=$i;done

Delete 'orphaned' patches and backup patches:

Do not delete /var/patch/applied or its contents.

rm /var/patch/*-*-*-*-*

For true emergencies or for patch install problems, you can delete patch backups:

rm -rf /opt/xensource/patch-backup/*-*-*-*-*

On the Pool Masters, we mount an NFS backup share on /mnt/backup.

Unmount the backup share and delete any 'hidden' files:

umount /mnt/backup && rm -rf /mnt/backup/*
mount -a

Windows Version: http://support.citrix.com/article/CTX129070

Linux Version: http://support.citrix.com/article/CTX129217

Incomplete and needs verification

This is a procedure to fix XenTools networking issues:

1. Remove network interface via XenCenter
2. Uninstall all Citrix XenTools packages from Add/Remove Programs
3. Remove Citrix from filesystem and registry
   • c:\program files\citrix
   • c:\program files (x86)\citrix
   • HKLM\Software\Citrix
4. Run in an admin command shell
   • Stop all running XenTools services
   • sc delete xenlite
   • winmgmt /resetrepository
5. Reboot
6. Check things out and remove any 'ghosted' or hidden network adapters
7. Reboot again
8. Add network adapter in XenCenter
9. Reconfigure the networking until it works properly again
10. Reboot
11. Reinstall XenTools patiently