Unified storage, a “single” storage solution that handles
both file-level and block-based storage, has become more common in data sheets
in recent years as manufacturers compete to complete every checkbox on the
speeds and feeds charts. I see the advantage behind the reduced device count
and simplified management interface; however, I believe that unified storage
only serves to place ink in a checkbox.

Most storage solutions that offer “unified storage” are the
same block-based storage with a software component bolted on to present a
volume on the network using NFS or CIFS/SMB. With this scenario, it is not
uncommon to get a block-based storage array with a NAS head-unit that provides
the NAS features; while this typically brings integration of the two within the
management interface, they are still two separate devices—with the NAS
head-unit leveraging a block-based volume on the array.
Now the integrated management of the block-based and
file-level components is pretty awesome. Who does not dream of that mystical
Single Pane of Glass? The downside is the limited NAS features typically
offered with a unified storage solution. Your corporate environment is most
likely heavy with Windows devices. What serves CIFS/SMB shares to Windows
clients better than a Windows Server? Storage manufacturers are forced to lag
behind on features and fault resolution as they attempt to play catch-up as
Microsoft releases new features into the Windows File Services. Alternatively,
some storage manufacturers offer their NAS head-units as Windows Storage Server
devices - is this still “unified”?
Windows Server integrates much better with your backup
solution than a unified storage solution. In fact, to protect your file-level
data a unified storage solution requires Network Data Management Protocol
(NDMP). NDMP is a networking protocol, as such errors can occur.
Troubleshooting faults in NDMP is a nightmare. Many backup vendors have built
proprietary versions of NDMP that mask the original error message. Scouring online
discussions turns up frequent posts of sysadmins trying to resolve an error
only to end with, “had to reboot the server to resolve the issue.” Maybe I am a
little conservative on this front, but I need to trust my backup solution and be
able to easily verify the restorability of my data.
A final thought before I ramble on about this all day …
Virtualization is a given nowadays; there are no valid
excuses to not be virtualized. What if we virtualized our file servers to
increase availability and reduce maintenance? Why would we not deploy file
servers, be it Windows or Linux based, as virtual machines that leverage
block-based storage? Now, for the crazy bit, what if we clustered these virtual
machines to create always online network shares for our users?
Many dedicated NAS solutions include numerous features that
are unique and provide much sought after capabilities, but unified storage
solutions only over promise and under deliver with their “jack of all trades”
design.
-Ryan M.
Ryan M. has over six years of
experience architecting and implementing SMB and enterprise data center
solutions. Currently a Solutions Architect at Great Lakes Computer, Ryan is focused on
using modern virtualization and storage technologies to reduce OpEx, increase
business continuity, and improve performance for customers.