I can perform a Site Backup via PowerShell "Backup -SPSite -Identity <url> -Path <file>" and also I can do a restore the same way "Restore -SPSite -Identity <url> -Path >file>" even to another SharePoint Server.
But I cannot do a farm backup neither via PowerShell nor via Central Admin. If I call e.g. "Backup-SPFarm -Directory 'D:\Backup' -BackupMethod Full -BackupThreads 10" the backup starts but never finishes. It always only creates 119 files in the specified
directory and what I can see in Windows Event log is that it backs up about 8 Databses and always stops at
SharePoint_AdminContent. With ULS Viewer I see some errors like <ERROR: Failed invoking job id {some id}> followed by <Unknown SPRequest error occurred. More information: 0x80070005>
I guess that there might be a database rights issue with that server, I run SharePoint 2010 foundation (actually Search Server Express) but MSSQL 2008 R2 Standard (not MSSQL Express) on the same machine.
Thanks, Dieter