Hi Oliver,
Does your customer use a Storage Array that supports Thin Provisioning (TP) and storage reclamation? If so, SFW 5.1 SP1 has added APIs for TP (for a few storage arrays right now, you can view the HCL at
http://seer.entsupport.symantec.com/docs/337683.htm) and this could potentially be used to get around the issue that the customer is having. Currently 3PAR and EMC CLARiiON with more to come).
If your customer has one of the aforementioned storage arrays, read the information below about TP and storage reclamation from the SFW 5.1 SP1 Administrators Guide (page 132). If you are not familiar with TP technology, I would suggest to research the topic and see if this would meet the needs of your customer (I think that this could be made to work since the storage allocation would be done at the array level instead of the server / disk group level).
If the customer does not have a supported storage array, scripting is an option, but an easier solution would be to create a number of 1 TB LUNs and place them into each disk group. When the volume hits 80%, or another percentage that you can specify, use the Automatic Volume Growth feature to add an additional 1TB of space to the volume. This is not exactly what you are looking for as you have to create the LUNs and have them in the disk group already, but it is better then getting a message that the file system is full and have to react to the problem when data can't be saved to the volume.
More information about Automatic Volume Growth can be found in the SFW 5.1 SP1 Administrator's Guide on page 216 at
http://seer.entsupport.symantec.com/docs/vascont/336.html
From the SFW 5.1 SP1 Administrator's Guide on page 132:
Thin provisioning is a technology to allocate disk storage on an as needed basis.
Disks that support thin provisioning are disks that are able to allocate storage as
data is written to the disk. In addition, some of these disks are able to reclaim
unused storage on the disk.
Disks that support thin provisioning have the following characteristics:
■ Disk storage allocated as data is written to the disk.
■ Unused storage may be reclaimed to minimize the amount of unused space on
the disk.
Note: Not all disk vendors support storage reclamation. Disks that support
both thin provisioning and storage reclamation are represented in the GUI as
a disk with a green colored sector with an asterisk (*). Disks that support only
thin provisioning are represented in the GUI as a disk with a red colored sector.
Reclaiming storage space from thin provisioned disks can be done for disk groups,
disks, or volumes. The operation to reclaim storage may take a significant amount
of time to complete.
I hope that you find this information useful (and if you do, please mark the question as resolved :-)). If you have additional questions, please post them as well.
Daniel