Many SMBs are unsure if or when they should move to networked storage from direct-attached storage (DAS). This is often because typical SMBs rarely have a dedicated storage organization or even a dedicated storage individual.
Let's take a look at some guidelines for moving from direct-attached storage embedded within physical servers, to network-attached storage (NAS) or a storage area network (SAN).
A network data storage primer: NAS and SAN
Network-attached storage is optimized for file sharing, is logically similar to a server's internal storage and does not require an additional server computer. NAS is really a purpose-built server specifically tuned and optimized for file sharing. Network-attached storage is connected to the client application servers or desktops over the TCP/IP Ethernet networks and is mounted as if it were an internal drive. The key thing to remember is network-attached storage can be generally easy for SMBs. It is only when the number of NAS systems begins to reach their maximum file or capacity limits, or proliferate, that management becomes a bit more complicated.
A storage area network is the connection of "block" storage devices to servers through a high-speed, storage-only network that is distinctly separate from the primary LAN. SANs today are frequently Fibre Channel (FC). However, the fastest growing SAN storage and storage network is iSCSI (SCSI protocol mapped to TCP/IP on Ethernet). It's Fibre Channel's history of complexity, difficult change management and frustrating troubleshooting that is the root cause of most of the anxiety.
The good news is that both Fibre Channel SAN networking vendors, as well as their OEMs, have gone a long way in alleviating many of those issues. They have made Fibre Channel SANs much easier. The better news is that iSCSI SANs are nearly as easy as NAS. In fact, many NAS systems also provide iSCSI.
There is also the virtual iSCSI SAN where the SAN storage runs as a virtual appliance. Virtual iSCSI SANs provide the simplicity of iSCSI with the low cost and convenience of DAS. And just arriving is the Fibre Channel over Ethernet (FCoE) SAN. This is aimed at providing the performance of FC with much of the ease of use associated with iSCSI.
There are five signs that indicate the time is right to move to networked storage:
1. Rapidly increasing storage operational administration and cost
If the amount of time being spent on operating, provisioning, managing, protecting and troubleshooting has escalated, networked storage can be a very viable solution. It centralizes all of the tasks, simplifying operations, provisioning, management, protection, troubleshooting, etc.
The same holds true if storage costs are increasing beyond comfort levels. This typically occurs because of overall storage utilization. Some applications eat up significant amounts of storage, whereas others grow at a more leisurely rate. But because DAS can't be shared, the growth applications can't take advantage of unused storage from other applications. This results in higher storage costs.
2. Mandatory regulatory or legal compliance
Networked storage makes it much simpler, easier and faster to meet compliance for Sarbanes-Oxley (SOX), the Health Insurance Portability and Accountability Act (HIPAA), Basel II, e-discovery and corporate governance. Compliance requires data retention. Networked storage typically has excellent snapshot and replication tools that facilitate data retention and make it easier because all of the data is centrally managed.
3. Increased storage induced scheduled and unscheduled application downtime
Direct-attached storage changes often cause disruptions to the attached applications. This means that those changes are often scheduled in off hours. The problem is that off hours are hard to come by in the 24/7global economy. DAS means the application cannot fail over to some other storage while the server's storage is being upgrade, increased, updated, etc. Networked storage can allow applications to remain online while changes are being made.
Networked storage additionally has a lower probability of causing unscheduled downtime because of a far superior ability to protect or heal systems when a fault occurs.
4. Tiered storage
Networked storage is designed to provide different tiers of storage for different data. This allows users to take advantage of lower cost lower performance HDDs, such as SATA, FATA and fat SAS, without sacrificing primary application performance. Direct-attached storage really can't do that.
5. Server virtualization has or will be implemented
Taking advantage of server virtualization's incredibly useful application availability functions requires networked storage. Implementing server virtualization without taking advantage of the increased application availability capabilities is ignoring one of the truly great benefits of server virtualization.
About the author: Marc Staimer is the founder, senior analyst, and CDS of Dragon Slayer Consulting in Beaverton, OR. The consulting practice of 11 years has focused in the areas of strategic planning, product development, and market development. With over 28 years of marketing, sales and business experience in infrastructure, storage, server, software, and virtualization, he's considered one of the industry's leading experts.
This was first published in May 2009