Xenserver Troubleshooting

The logs to check for Xenservers are:

For disk related issues: /var/log/SMlog
For other Xenserver related issues: /var/log/xensource.log

Some Xenserver related issues are:

• Disk not coalescing (freeing upi space on a thinly provisioned host): Usually, disk space on the local storage shouldn't go beyind 85%. If the disk space usage is too high, there won't be enough space to coalesce (freeing up unused space). As well, if the coalescing is not being done properly, tail this file and do a rescan of the disk from Xencenter and you can see the status of coalescing and how much space can be reclaimed.
• Xenserver accessible through SSH, but goes on connecting on Xencenter: You can execute an xe-toolstack-restart command to restart associated services of Xen to see if the issue goes away. You can check the xensource.log for details. You can always contact Citrix support.
• Removable storage not visible on Xencenter:
  
  Sometimes, the removable storage will not be visible in Xenserver. The removable storage (USB storage) is presently used for Xackup backup drives on host 4gh4xen and 4gh6xen-to. You need to login to the server and perform the below:
  
  # modprobe -r usb_storage
  # modprobe usb_storage
  
  Now, peform a rescan of the drive by clicking Rescan and the disks will then be visible.
  
  [Image: xen.jpg]
  
  Once the disks are visible, go to the VM in question, click Storage tab, Attach Disk, and select the disk and click Attach. Repeat it for all the disks that need to be attached.
  [Image: xen1.jpg]

• Network doesn't come up even after the IP is setup:
  You may need to check what the MAC address setup on the IP file, for example, on CentOS, the /etc/sysconfig/network-scripts/ifcfg-eth0 file and edit the file to match the MAC address you see for the NIC card of that VM in Xencenter