Home > Storage > PowerStore > Virtualization and Cloud > VMware Horizon 8 with Dell EMC PowerEdge R6525 Servers and Dell EMC PowerStore 9000 > Block storage
PowerStore presents storage to external hosts through either block or file interfaces. Block storage is the most common datastore path for virtual machines. The various speeds and protocols offered make it ideal for performance. NFS is also used but is less common. PowerStore supports 25 GbE and 32 Gb FC connections for broad compatibility and performance requirements. For instructions and best practices for configuring hosts, see the Dell EMC PowerStore Host Configuration Guide.
Configuring multipath I/O (MPIO) is critical to achieving the best performance from VMware hosts and should be configured properly. For MPIO configuration guidance, see the document Dell EMC PowerStore: VMware vSphere Best Practices on the PowerStore Info Hub.
The large number of small IOPS generated from VDI environments benefit greatly from MPIO round robin and rapid-path switching. The use of rapid-path switching can help improve VM performance. For this test, Disk.DiskMaxIOSize is set to 1024 (1MB).
The MPIO configuration that is used for this configuration is as follows:
This configuration provides optimal pathing with failover protection and path discovery.
See Dell EMC PowerStore: VMware vSphere Best Practices and Dell EMC PowerStore Host Configuration Guide for guidance on setting MPIO and other VMware best practices.
Note: Applying best practice settings for network and MPIO are critical to optimizing the performance of a VDI workload at scale.
Using iSCSI for block storage allows convergence of storage and networking infrastructure. It requires careful planning to ensure adequate bandwidth and fault tolerance. Redundant networks are preferred for data availability.
With iSCSI, increasing the maximum transfer unit (MTU) size from a 1,500-byte standard frame to a 9,000-byte jumbo frame is also highly recommended. The use of jumbo frames allows greater packet efficiency for higher bandwidth. Using jumbo frames is not a requirement but is strongly recommended. Combined with the 25 GbE connectivity available in PowerStore, iSCSI can handle demanding workloads and high throughput requirements when configured properly with best practices applied. All devices in the iSCSI data path in this configuration (PowerEdge hosts, switches, PowerStore) are configured for jumbo frames with an MTU of 9,000. This change reduces network switch loads as a smaller number of large packets are processed.
Another benefit of using Ethernet infrastructure for iSCSI is the ability to share the network with file services. This use requires planning to ensure that there is enough bandwidth for all services, but it also reduces the hardware requirements. The use of different VLANs allows traffic prioritization to ensure that block traffic has the highest priority.
In this environment, iSCSI traffic is configured to use a dedicated VLAN. Two 25 GbE ports in I/O Module 1 on each PowerStore node are dedicated to iSCSI, for four ports total. Jumbo frames is enabled on all network devices in the data path with MTU = 9000 bytes. PowerStore automatically configures ports in redundant pairs across I/O modules for redundancy and to optimize throughput.