While defining a backup specification by clicking in the GUI, the order of selecting and deselecting hosts and directories will influence the way objects are defined in the datalist. When selecting client "C1", the different filesystems on this client will get selected automatically. Let's assume there is "FS1", "FS2" and "FS3" and we deselect "FS1". The result of this action would be a datalist including 1 "HOST" object with "FS1" excluded.

HOST "C1" C1
{
	-trees
		"\"
	-exclude
		"FS1"

Instead of selecting the host, it would also be possible to select "FS2" and "FS3". In that case the datalist would include 2 objects:

FILESYSTEM "FS2" C1:"FS2"
{
} 

FILESYSTEM "FS3" C1:"FS3"
{
} 

Note that the examples above are only cryptic and a filesystem on a *UX server would typically be defined with a path starting with a "/". Also in case of a windows client the object would be WINFS rather than FILESYSTEM.

Now, it is important to understand the implications of both methods.

1. While the initial data selection may be more or less similar (FS2 and FS3), that may change when another file system is added to the system, e.g. "FS4". In the case of the HOST object definition, the new file system will automatically be included in the backups, not in the other case. So the choice for either a HOST or a FILESYSTEM/WINFS definition may be intentional.

2. In a case where different datalists are used for full and incremental sessions, it is extremely important to make sure the objects are defined the exact same way in both datalists, so either both HOST or both WINFS/FILESYSTEM. Additionaly, it's required to have the 3 components that make up the object definition identical: hostname, mount point or filesystem, description. In short: the complete line containing either the HOST or the WINFS/FILESYSTEM identifier need to be identical! Only then the objects defined in both datalists will match and the incrementals will be based on the existance of protected full backups for this object.

You may be interested to some of my other Support Tips too: Support Tips listed per category.