Diskeeper Defrags Compellent SAN

Storage Area Networks are a substantial development for computing. They allow the return of substantial system resources – both in network traffic and processing times – that were previously robbed from higher priority business processes, and provide a level of storage efficiency never before seen.

Many SANs, such as those manufactured by Compellent, include a technology called thin provisioning. This technology allows for data blocks to be written as needed, instead of allocating large blocks of space that may or may not ever be used.

But despite their advanced technology, SANs are still subject to one of the oldest enemies of system performance and reliability: file fragmentation. File fragmentation occurs at the file system level, causing files and free space to be shattered into thousands or even tens of thousands of fragments. Not even the high tech approach of a SAN can overcome the problem.

While the SAN allocates space using thin provisioning, the file system writes data wherever it finds space. If data is written to a ‘high’ logical cluster number (say, cluster 200), all clusters from zero to 200 are then allocated even if they are not used. As new files are added, or data is added to an old file, or data is deleted, this difference between file system disk allocation and storage system thin provisioning can contribute to fragmentation, over-allocation, and less efficient use of storage space.

Fully automatic defragmentation on SANs, such as that provided by Diskeeper fully automatic defrag, allows the file system to write over deleted blocks, thereby preventing over-allocation.

"Diskeeper has really helped to keep our core servers on our Compellent SAN running faster and has allowed us to reclaim the extra space that would have otherwise been lost on our SAN," said Kevin Fitzpatrick, IT Director with ROEL Construction Company in Salt Lake City, Utah.

Diskeeper’s proprietary InvisiTasking technology allows defragmentation in real time, invisibly, in the background. Scheduling is never required and there is never a negative performance impact on the system. Best of all, performance and reliability are consistently maximized.

"All of our systems are servers that connect to a Compellent SAN," said Chad Westerhausen, System Administrator for DGC Power Cooperative in Beulah, North Dakota. "We have pretty much been running Diskeeper on our SAN servers since we started using it. The servers run better with Diskeeper installed."

"I also like it because it runs in the background when the system is not busy instead of having to schedule a certain time to defrag," Westerhausen added. "After the initial installation, I rarely have to do anything with it."

Diskeeper ensures that the full benefit of advanced solutions such as SANs deliver their full benefit.