Database Reference
In-Depth Information
cluster. If you have an insufficient vFRC resource on a server, you may not be
able to migrate or power on a VM.
Note
Performance tests conducted by VMware using the Dell DVD Store to
simulate an ecommerce site with vFRC showed up to a 39% performance
improvement with certain configurations. A number of statistics can be
useful for monitoring and tuning vFRC. For detailed information on vFRC,
performance test results from VMware, and vFRC stats, refer to
Fusion-io ioTurbine
ioTurbine is caching software from Fusion-io that leverages the Fusion-io ioMemory
range of high-performance flash devices, such as the SLC- and MLC-based ioDrive and
ioScale PCIe cards. ioTurbine creates a dynamic shared flash pool on each ESXi server
that can be divided up between cache-enabled VMs based on proportional share
algorithm. By default, each VM is assigned the same shares and thus get an equal
proportion of the available flash cache resource pool.
Like VMware's vFRC, ioTurbine is a read cache, and all writes are sent through to
persistent storage while simultaneously being cached. Unlike vFRC, there are no manual
parameters to set on a per-VM basis to size the cache or the blocks that are cached. This
automatic and dynamic sizing of the flash cache of each VM is useful where you have
lots of VMs that can benefit from caching or where you have flash devices of different
sizes on different hosts. It reduces the management overhead.
Figure 6.41
displays a high-level overview of the ioTurbine architecture, including
Fusion-io's Virtual Storage Layer (VSL) driver. As of ioTurbine 2.1.3, which supports
vSphere 5.5, the VSL SCSI driver is used by default instead of the VSL block driver.
This can provide improved performance and better resiliency.
