ML 10.8.3: issue with netuser login

Hi all,

I've setup a ML 10.8.3 MacMiniServer. Latest Servertools are installed. DNS and OD are up and running perfectly. Due to the fact, that I need performance and reliability for the the netusers homefolders, I've created a folder NetUsers on a RAID10 volume (two external RAID1 HHD housings linked together as a RAID0 using the software RAID function in diskutility) and started creating users with their homefolders located there. The old Users-folder is still in place for local server users. What happens now is that netusers who have their homefolders located in the NetUsers folder on the RAID10 volume are able to login to any Mac client. So far, so good. But if I use quick user switch and try to login a second NetUser on the same client while the first one is still logged in, the log on the Mac client shows this:

May 15 22:31:49 ws02.fritz.box authorizationhost[1190]: ERROR | -[HomeDirMounter mountNetworkHomeWithURL:attributes:dirPath:usernam e:] | PremountHomeDirectoryWithAuthentication( url=afp://macminiserver.homenet/NetUsers, homedir=/Network/Servers/macminiserver.homenet/Volumes/filevolume/NetUsers/user 01, name=user01 ) returned 16

I did some research and found out that this only happens to netusers with the homefolders stored on the RAID10 volume. Any netusers created with their homefolders stored in the original Users folder are able to login to the Mac client while another netuser is already logged in.

I've checked all the permissions (UNIX permissions and ACL) and find them all identically.

Is somebody able to help me with this issue? What does errorcode 16 mean? I've googled a lot but cannot find a list of errorcodes and descriptions of them. Any help is highly appreciated!

BR

Jens