Thursday, November 19, 2009

Disk ID issues with disk cloning on Windows Clustering

In windows clustering Disk ID is used to determine disk uniqueness. If you are using a SAN or other utilities that clone a disk and try to add another disk that is already clustered storage your disk will come online as reserved. Cluster storage takes control of this disk assuming that its meant to be the same disk. This would and can be great if you need to restore a cluster disk that failed and have a disk clone of that disk. When it would get restored the cluster would match on the disk id which would allow the clustered application or other clustered services to work without reconfiguration. Where this can effect you if for example you have a SAN that supports disk cloning which would indeed copy the disk id. That disk was a sysprep based windows LUN and when attached to a cluster node will become reserved. To prevent this from happening you can change the disk id from within diskpart. Best way I found is attach your LUN to a non cluster member that way it won’t become reserved. To run the commands below you will need to have the disk in the online state. (replacing the disk number with yours).


DISKPART> rescan

Please wait while DiskPart scans your configuration...

DiskPart has finished scanning your configuration.

DISKPART> list disk

  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---
  Disk 0    Online          139 GB      0 B
  Disk 2    Online          105 GB  1024 KB

DISKPART> select disk 2

Disk 2 is now the selected disk.

DISKPART> uniqueid disk id=11170901


You can come up with your own disk id numbering method. Date based methods work pretty well for smaller environments. I have not yet automated this but plan to do so to make this more scalable. Once your disk ID is changed you can attach this disk and attach this to all your nodes in your cluster and when you run add clustered storage the disk rescan will find this to be a new disk now that the disk id is different then all of the other clustered storage.

Wednesday, November 18, 2009

Laptop uses WLAN before LAN

This comes up when I use my laptop on a dock where I have wireless enabled and Ethernet plugged into the dock. Its common for laptop users to want their wireless enabled while roaming. To fix this issue you can change which connection is used first.

Windows 2003/XP

  1. Start Button
  2. Control Panel
  3. Network Connections

Windows 2008/7/Vista

  1. Start Button
  2. Control Panel
  3. View Network Status and Tasks
  4. Change adapter settings (Vista is Manage Network Connections)
  5. To get the Advanced menu up press the ALT key

advanced options

Once you are able to get to the advanced menu click on advanced settings.

advanced dialog

In the upper section you can move a network connection up or down. That connection on the top will be tried first. In the case of the WLAN always online and plugging into dock once the LAN connection comes online WLAN will not be used until LAN connection is unplugged. This can be issues on servers or other computers with more then one network connections but more commonly laptops use two different network connections for the same network purpose.

Windows 2003/XP Zip Error Coping File or Folder

If you try to copy an application file and get An error occurred while copying the file. At the time other files would extract. Go to properties on the zip file and on the general tab click the unblock file. If your having issues with all of the files your zip file might be incomplete or corrupt.