Database Reference
In-Depth Information
Figure 6.45
PernixData FVP acceleration for SQL Server 2012 latency.
When FVP cannot flush the uncommitted data to primary persistent storage fast enough
—that is, when more hot data is coming in than there is flash space available—FVP
will actively control the flow of the new data. This means that FVP will artificially
increase the latency, ultimately controlling the rate at which the application can send,
until the flash cluster has sufficient capacity and returns to normal. FVP does not
transition to write through, even when it is under heavy load. Applications normally
spike and are not continuously hammering the data path 100% all time, so FVP flow
control helps smooth out the “spikey” times, while providing the most optimized
performance possible.
Caution
Migrating a VM in an FVP flash cluster, in certain network failure scenarios, or
when the local or replica flash device fails, FVP will automatically change the
write back policy to write through. This ensures data protection, while degrading
write performance. However, reads may still be accelerated by requests being
serviced from the remainder of the flash cluster. When the issue is resolved the
policy will be automatically returned to write back. For more information, see
the “Fault Tolerant Write Acceleration” white paper on
http://pernixdata.com
and
standard part of the FVP Fault Tolerant Write Acceleration Framework.
SQL Server on Hyperconverged Infrastructure
If there is one technology trend that is revolutionizing the enterprise data center more
than just flash alone, it is hyperconvergence. This is where storage and compute (CPU
and RAM) are provided in a single package and connected by standard Ethernet
networks. By far the leader in this sector of the market is Nutanix, with its Virtual
Computing Platform. This section covers key aspects of SQL Server performance and
