The following table shows information I was using to compare various Windows HA file and print solutions, including MSCS, VMware, VMware+MSCS, DFS, VMware+DFS and stand-alone servers. There are no recommendations, and most need to be adjusted or at least considered for your environment, but it might help crystalise your thoughts as it did mine.
Comparison Microsoft server Clustering VMware HA Microsoft Clustering on VMware HA DFS Stand-alone server(s) VMware HA with DFS for file shares Highly Available Y Y Y N N Y Satisfies SLAs ? ? ? ? ? ? Maximum nodes 8 Limited by host hardware 2 N/A N/A Limited by host Failover time <2 minutes VMotion or server startup time <2 minutes SPF SPF VMotion or server startup time Single server Disaster Recovery – Software Failure <2 minutes Snapshot, server rebuild or manual recovery procedure <2 minutes SPF SPF pshot, server rebuild or manual recovery procedure Single server Disaster Recovery – Hardware Failure <2 minutes < 30 seconds < 30 seconds SPF SPF < 30 seconds Licensing 2003 Enterprise per node DataCentre + CALs (depending on VM design) DataCentre + CALs (depending on VM design) 2003 Standard 2003 Standard 2003 Standard Hardware Failure – Data Communications Single/teamed NIC for prod interface NIC redundancy depending on virtual solution NIC redundancy depending on virtual solution + cluster-specific requirements Teamed NIC Teamed NIC NIC redundancy depending on virtual solution Hardware Failure – HBA Single HBA per node HBA redundancy depending on virtual solution HBA redundancy depending on virtual solution Single HBA Single HBA HBA redundancy depending on virtual solution OS Disk Configuration Basic Dynamic Basic Dynamic Dynamic Dynamic Hardware utilisation Physical servers Virtual servers Virtual servers Physical servers Physical servers Virtual servers Cost allocation Cost model required Cost model required Cost model required Per server/LUN Per server/LUN Cost model required Scalability/Flexibility – adding new nodes/LUNs Y Y Y N N Y, DFS for file Manageability MSCS skills required VMware skills required Complex combination of both technologies DFS skills required Existing skills, but increased per server DFS and VMware skills required User access to shares via UNC Single name Multiple names Single name Single name Multiple names DFS namespace Future proofing – migration to new hardware/OS Moderately complicated migration Relatively simple upgrade path, reattaching LUNs or adding another VM Moderately complicated migration Relatively simple Relatively simple Relatively simple Hardware on Vendor HCL ? ? ? ? ? ? Backup/restore ? Standard file backup VCB or ? Standard file backup Standard file backup VCB or ? Printer administration Simplified with Cluster 2003 Duplicated effort on each print server Simplified with Cluster 2003 N/A Duplicated effort on each print server Duplicated effort on each print server Service and Event Monitoring Cluster monitoring required Standard monitoring for virtual servers, host monitoring required Cluster monitoring for virtual servers, VMware host monitoring required Standard monitoring Standard monitoring Standard monitoring for virtual servers, host monitoring required
1. Basic disks on a Microsoft server cluster can be extended if new space is visible on the LUN. The disks cannot be dynamic in MSCS.
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