Storage management challenges are often being addressed by either
storage hardware vendors or storage software developers. It is time for
file systems to step up and offer a little help to the process. Most of
the third-party software and hardware actually do a good job of solving
many of the problems, but there are a few areas where the file system
could help out like thin provisioning, backup and deduplication.
The file system always has an advantage over any hardware or third-party
software solution; it has an exact understanding of what is going on
and it has that understanding typically at a better level of
granularity. Where the file system can help the storage management
process is either by exposing that information via an API set or
communicating that information directly to the hardware or software.
There are some examples of file systems doing this today. For example as
we discuss in our Thin Provisioning White Paper, thin-aware file
systems can communicate directly to thin-enabled storage systems to
allow the hardware to reuse deleted blocks. While some storage systems
can do this externally, having the integration at the file system can
lower the amount of processing work that the thin provisioned system
needs to perform and release that capacity in real time. Another example
is that some file systems can communicate to backup deduplication
devices or software exactly what blocks have changed in the file system
so only those blocks need to be examined for redundant data instead of
scanning the whole file system.
NAS systems, in order to provide these services, typically must have
ownership of the entire storage system. In fairness, when they do have
ownership over the storage they provide much of the functionality
listed above, but it all has to stay within their ecosystem. They don't
typically support third-party storage or communicate to third party
backup applications. The NAS file systems that do support third-party
storage hardware should now be working on communicating free space or
changed blocks to those hardware platforms to further add value to the
software only NAS model.
File systems, for the most part, have been focused on replacing much of
the storage hardware system's functionality by adding capabilities like
snapshots, compression and deduplication. This is good, the hardware
vendors need competition. The file system vendors though should look
also at augmenting what the storage hardware can do, allowing the user
to select what makes the most sense for them.