Figure 3, Ha reference architecture, Ha reference architecture figure 3 – Dell PowerEdge R820 User Manual
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Dell Virtualization Solution for Microsoft SQL Server 2012 using PowerEdge R820
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HA Reference Architecture
Figure 3.
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Brocade 5100
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Brocade 5100
PowerEdge R820
Brocade 5100
PowerVault MD3620F
Hyper-V Cluster
The two Dell PowerEdge R820s are members of a Hyper-V failover cluster. Each of the VMs would be
active on one of the R820s. If the active node fails, all the VMs will failover to the passive node.
For this exercise, we are using pass-through disks for virtual machines. During live migration, the LUN
(volume) disconnects and connects back to the virtual machine on the other node. We could observe a
slight delay 2 to 5 seconds to get the virtual machine running on the other node. This delay is
experienced only when pass through disks are used.
This delay may be avoided using iSCSI storage or fixed virtual hard disk for SQL Data files. This enables
virtual machine to migrate between multiple hosts. In addition, this also allows configuring fail over
cluster at the Virtual machine level (as an alternative to Hyper-V clustering).
Refer to
for more information on configuring pass-through disks to
virtual machines.
Performance and Scalability of Virtual Machines achieved
We conducted several experiments to analyze the database consolidation capabilities of R820. The
tests were focused on the impact on the SQL Server performance due to Virtual Machine consolidation
to a single R820 server.