Dell POWEREDGE R720XD - Manual (Page 14)

Dell High Availability and Disaster Recovery Solutions Using Microsoft SQL Server 2012 AlwaysOn
Availability Groups
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Advantages and limitations of implementing AVG on shared storage
Advantages:
 Cost effective HA and DR solution for Enterprise Customers
 Instance level protection using FCIs
 Support of multi-subnet FCI clustering enables a DR solution using AlwaysOn with multi-subnet
FCI
 Flexible failover policy for granular trigger events for automatic failovers
 Support for variety of storage types and configurations at each site (iSCSI, FC, SAS etc.)
 May benefit from enhanced SAN features
Limitations:
 No Automatic failover/failback support for FCI when it is combined with AVG functionality
AVG deployments on hybrid (HDD and SSD) storage
In HA and DR solutions, it is always a good practice to use high performing drives such as SSDs in the
primary site to get faster failover benefits and high performing databases within the primary site. Dell
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th generation servers (such as the R720 and R820) come with support for front-loading PCIe SSD
drives.
Benefits
Dell™ PowerEdge R720 and R820 servers support up to four 2.5-inch 350G front-access PCIe SSDs drives.
Figure 7 shows a possible deployment of AlwaysOn Availability Groups on the PCIe SSDs drives of Dell
PowerEdge servers.
AVG deployments on SSD and HDD Figure 7.