Hi,
as far as I know, (Cluster config and multi-tennant might hold other information), you cannot split the data sections. There is one database set and one data path (alf_data).
CIFS, Webfav et.al. are only different methods accessing the data, you cannot decide to store webdav data on another place than CIFS data.
You could theoretically move (under linux) some subfolder to a different drive, but think about it - then you have part of your data on drive a and part on drive b - and you MUST have all data 100% perfect in sync ! So a drive, that breaks down, needs a guaranteeeeeed perfect restore fit in order to work, or you have to restore all data anyway, so what is the big win ?
Best you move the complete /alf_data to a different drive. The question is, what happens if the drive fails - can you afford waiting a day or two until you have a replacement drive ? And can you afford loosing a days work ? Is one of the questions NO, then go get another two drives for a RAID 1 at least (mirroring drives). One drive to run the RAID, one in backup to replace a broken one ASAP. And yes - harddiscs do fail - much more often, than one would expect.
Norgan