Dell PowerEdge R820 - Manual (Page 12)

Dell Virtualization Solution for Microsoft SQL Server 2012 using PowerEdge R820
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SQL Server Storage Layout Figure 4.
Global Hot Spare
LUN 1
(VM OS VHD)
LUN 2
(SQL-Data LUN)
LUN 3
(SQL-Data LUN)
LUN 7
(SQL-Data LUN)
LUN 6
(SQL-Data LUN)
LUN 5
(SQL-Data LUN)
LUN 4
(SQL-Data LUN)
LUN 8
(SQL-Data LUN)
As shown in Figure 4, we have created a dedicated disk group of 8 disks (RAID 6) for hosting the VM
operating systems; separate fixed size VHDs were created out of the disk and assigned to the individual
VMs.
For hosting the database files, we have created dedicated disk groups for each of the VMs on the
PowerVault MD3620F storage. Each SQL Database LUN comprised of 8 disk drives configured using RAID
1+0. Using dedicated database LUNs ensures minimal impact on the database performance due to the
multiple VMs being stressed at the same time. The databases LUNs were configured as pass-through
disks to help reduce the I/O overhead further on the virtual machine.
We observed that each of the medium and large baseline VMs delivered an Avg. Response Time (sec) of
0.007 and 0.015 for a user load of 12 and 24 at average processor utilization of around 80 to 90%. The
average disk reads/sec for the VMs was around 0.008. For the further result comparisons, we would be
using the user load of 12 & 24 as the evaluation point.
Results and Analysis
Figure 5 and 6 shows the database transactions per second and SQL Server batch requests/sec achieved
on a single R820, for medium and large VMs.