How do I get the most performance from my SAN?
At some point, a SAN administrator will realize that the SAN storage is no longer performing as well as it once did. Investigating the cause of the performance slowdown usually indicates problems with free space or available storage.
The administrator may wonder what is causing all the unexpected I/O, and increasing the amount of storage available is usually the easiest solution. However, in many cases adding storage is unnecessary because storage on the SAN is not the problem.
One of the most significant issues, and the most unrecognized, is the excessive amount of unnecessary I/O in the SAN environment. With the implementation of a SAN, many Windows Server administrators believe that excessive I/O, which they accepted and dealt with when using DASD storage, has gone away.
Storage admins often overlook excessive I/O when evaluating the problem of reduced SAN efficiency. When SAN performance problems are noticed, the knee jerk reaction is to add additional storage, with the presumption that the lack of free space is causing the SAN to slow down. However, both overall performance and storage efficiency can be affected by the tidal wave of unnecessary I/O that occurs when Windows Server writes data out to storage, regardless of whether that storage is DASD, NAS, or SAN.
Effects of Excessive I/O on SAN storage
The effects of excessive I/O in SAN storage often manifest in reduced application performance and inefficient use of storage. Application response times begin to degrade, the time necessary to load large files and applications grows longer, and the overall user experience is negatively impacted.
End-users begin to feel that their computer is slowing down, leading to help desk calls with complaints about network performance or other problems. The reality is that the massive amount of unnecessary I/O is causing data manipulation times to increase to the point where the delay becomes perceptible to the end-user.
V-locity® I/O optimization software uniquely addresses the unnecessary I/O patterns of reads and writes by aggregating data on writes to perform sequentially while caching reads on available server memory without contention to the application. As a result, V-locity boosts application performance by 50% or more by (1) maximizing the efficiency of every single I/O from write requests that leave the server and (2) caching the most active data from read requests using available server memory.
Read I/O Optimization – Much of the I/O traffic moving through the infrastructure shares similar data, yet every byte of that data travels the entire distance from server to storage and back for every I/O request, even when it is frequently accessed data. IntelliMemory™ technology addresses this read request inefficiency by caching the most active data in the server’s available memory. Should an application require more memory, V-locity serves memory back to the application to ensure there is never a case of memory starvation or resource contention. Condusiv Technologies’ self-learning caching algorithms have set the gold standard for the industry as they are OEM’d by eight of the top ten largest PC manufacturers in the world.
Write I/O Optimization – V-locity’s IntelliWrite® technology optimizes I/O write operations, eliminating the performance penalties associated with the Windows OS, splitting files into pieces and writing each piece to a different logical location within the SAN or NAS. V-locity is aware of space allocation and aggregates write to behave sequentially—requiring less I/O for every file written. Subsequent reads also benefit, since the only minimum, I/O is required to fulfill the request. As a result, only productive I/O requests are processed across the entire infrastructure, enabling more data to be processed in the same amount of time.
V-locity I/O optimization is tailored for virtual environments that leverage a SAN or NAS as it proactively provides I/O benefit—improving storage performance and benefiting advanced storage features like snapshots, replication, data deduplication, and thin provisioning. Since V-locity optimizes I/O at the server level, it is complementary to all SAN and NAS storage systems and media types (e.g., HDD or SSD).
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