From Informationweek’s Storage Blog
What keeps many organizations from seeing significant improvement generally centers on two areas that have plagued some thin provisioning implementations; conversion to thin and reclamation….
The second issue that has plagued thin provisioning is that during use, deleted items do not properly get reclaimed. This is because most file systems do not really delete data when you give the delete command, they just set the data as eligible to over write. If you go through a big house cleaning operation on a volume, that freed up space is not reallocated to the global storage pool that thin provisioning storage systems count on. It stays with the volume.
The result of these two factors is that thin provisioned systems put on a little weight both initially and over time. While some thin provisioning is better than no thin provisioning these challenges lead to the poor results on the survey. Companies like 3PAR, HDS and DataCore have all announced technologies that can address both the conversion to thin issues as well as the ongoing space reclamation issues.
With these technologies companies can intelligently convert to thin to see immediate storage savings and can keep their volumes thin over time. Thin provisioning is more than a check mark feature, it is a serious technology that when all the challenges are properly addressed can save significant storage costs in the enterprise.