White Papers

vStart 1000m for Enterprise Virtualization using Hyper-V – Reference Architecture
Dell Inc. 21
6.6.7.2 CSV Requirements
· All cluster nodes must use Windows Server 2008 R2.
· All cluster nodes must use the same drive letter for the system disk.
· All cluster nodes must be on the same logical network subnet. Virtual LANs (VLANs) are
required for multi-site clusters running CSV.
· NT LAN Manager (NTLM) authentication in the local security policy must be enabled on cluster
nodes.
· SMB must be enabled for each network on each node that will carry CSV cluster
communications.
· ―Client for Microsoft Networks‖ and ―File and Printer Sharing for Microsoft Networks‖ must be
enabled in the network adapter’s properties to enable all nodes in the cluster to communicate
with the CSV.
· The Hyper-V role must be installed on any cluster node that may host a VM.
6.6.7.3 CSV Volume Sizing
Because all cluster nodes can access all CSV volumes simultaneously, standard LUN allocation
methodologies are used and are based on performance and capacity requirements of the workloads
running within the VMs themselves. Generally speaking, isolating the VM Operating System I/O from the
application data I/O is a good start, in addition to application-specific I/O considerations such as
segregating databases and transaction logs and creating SAN volumes and/or Storage Pools that factor
in the I/O profile itself (i.e., random read and write operations vs. sequential write operations).
CSV’s architecture differs from other traditional clustered file systems, which frees it from common
scalability limitations. As a result, there is no special guidance for scaling the number of Hyper-V Nodes
or VMs on a CSV volume other than ensuring that the overall IO requirements of the expected VMs
running on the CSV are met by the underlying storage system and storage network.
Each enterprise application that is planned to run within a VM may have unique storage
recommendations and even perhaps virtualization-specific storage guidance. That guidance applies to
use with CSV volumes as well. It is important to keep in mind that all VM’s virtual disks running on a
particular CSV will contend for storage I/O.
Also worth noting is that individual SAN LUNs do not necessarily equate to dedicated disk spindles. A
SAN Storage Pool or RAID Array may contain many LUNs. A LUN is simply a logical representation of a
disk provisioned from a pool of disks. Therefore, if an enterprise application requires specific storage
IOPS or disk response times, all the LUNs in use on that Storage Pool must be considered. An
application which would require dedicated physical disks, were it not virtualized, may require
dedicated Storage Pools and CSV volumes running within a VM.
6.6.8 High Availability
In order to maintain continuous connectivity to stored data from the server, the controller level fault
domains are established to create redundant I/O paths. These fault domains provide for continuous
connectivity with no single point of failure. Domain 1 includes connections through the top 5100, then