Challenges


The medium-sized enterprise can be a challenging environment for the IT professional. These businesses have typically reached a point of maturity where they need dedicated servers to perform critical operations like email, financials and business production. For many mid-sized organizations, the standard disk that originally came in the server can no longer deliver the kind of performance needed to support these business-critical applications. This scenario will often prompt the IT team to investigate alternatives like 15K SAS drives or internal drives that are striped to increase performance. They may also look at faster external storage arrays.


While these upgrade options may make sense in some cases, there are challenges to improving the performance of servers with existing internally mounted storage--the primary one being implementation. The first option is to simply replace the existing internal storage with faster disk drives. This scenario entails a disk controller upgrade plus the need to back up and restore all the data. Another option would be to purchase external storage and then have the data migrated to it. While this is a more straightforward approach, it’s substantially more expensive than internally mounted drives. A final option is to implement a SAN and share that storage across multiple servers. While there are plenty of reasons to implement shared storage, there’s a cost and complexity associated with it. If the primary goal is to improve the performance of a few specific applications, shared storage may be overkill.


The biggest drawback to the above mentioned implementation scenarios is that there’s no guarantee that server performance will be substantially improved, especially when simply replacing old hard disk drives (HDDs) with new ones that are only slightly faster. Similarly, an external storage solution may be shareable and more upgradeable but the underlying storage technology, mechanical HDDs, are still essentially the same—and so are their performance constraints.



Solutions


Instead of relying on traditional spinning disk technology to upgrade performance, a better solution could be to augment the current server environment with internal SSDs. The medium-sized enterprise may be the ideal candidate for today's server-based SSD technology, as many of these businesses are experiencing performance constraints but not necessarily capacity issues. SSDs can be an effective method for ‘bumping up’ storage performance, especially IOPS, without adding capacity, which is often the case with HDD-based solutions. Installing SSDs in servers can provide a significant performance increase precisely where it’s needed.


An ideal use case for server-based SSDs is an enterprise looking to increase performance over capacity in a finite set of servers. For example, Micron Technology’s RealSSD™ P300 SSD generates 16,000 write IOPS as compared to a 15K RPM SAS hard drive, which generates only about 350 IOPS. Unlike the various storage options listed above, this performance boost can be added with minimal disruption, if any, to the server.



Performance Bottlenecks


When considering SSDs, it’s important to understand the root cause of many performance bottlenecks. Often, these problems are caused by a few proportionately small files, not one big file. For example, these could be log files that track the transactions of a database or email application, or small files that are constantly being read from and written to. The other common culprit is swap files used by operating systems and applications when physical RAM has been completely allocated. As is the case with log files, these are typically small files that have very active read/write patterns.


SSD technology is an ideal solution for these common read/write storage challenges. For example, a drive like Micron’s RealSSD P300 can be installed into an available slot in the server and the existing HDDs can still be leveraged to store the bulk of the data. The SSD works just like a standard HDD, only faster. Once the drive is formatted, the final step is quite simple--all that’s required is a quick visit to the application or operating system configuration section to change the log file or the swap file over to the new SSD. In some cases there may be a need to restart the application or server, but this is rare.


Implementing SSDs can eliminate storage performance issues in a cost-effective and straightforward manner - with zero data disruption. Another benefit of SSDs, when used in this manner, is that no change is required to the data protection process. The primary data that needs to be protected is where it always was. No special copy jobs or complicated mirroring setups need to be made. The log files and swap files are temporary in nature and don't typically need any special backup procedures.



Evaluating SSDs


It’s important to note that not all SSDs should be created equal. Performance and reliability can vary greatly between manufacturers so it’s important to look for an SSD vendor that builds the SSD, develops and tests the firmware in-house, and designs and manufactures the NAND Flash memory that goes inside. These SSD suppliers, like Micron, have the technical expertise to architect and optimize the drive’s memory, resulting in a higher performing and more reliable device. Also, most enterprise-level SSDs use SLC-based memory, which has significantly higher resiliency to failure than the type of Flash used in consumer products.


When evaluating SSDs, it’s also important to look for performance data produced with the drive’s write cache turned off as this will result in more realistic performance numbers. Additionally, it’s critical to evaluate a drive’s ‘steady state’ performance as opposed to its ‘out of the box’ output in order to get a more accurate measure of the drive’s long-term performance capabilities.



Conclusion


Given the significant IOPS advantage that SSDs provide over traditional disk drives make it a natural solution for today’s storage performance challenges. Additionally, server-based implementation of SSD technology is a straightforward and efficient way to maximize performance where it’s needed—close to the application. The significant IOPS increase coupled with its ease of implementation make it a compelling alternative for medium-sized enterprises that need answers to storage performance problems without the complexity--and uncertain effectiveness--of the hard disk-based alternatives.

George Crump, Senior Analyst

Micron Technology is a client of Storage Switzerland