Knowledge Base

What is vSphere Metro Storage Cluster?

vSphere Metro Storage Cluster is a new storage configuration for VMware vSphere environments. A product must be certified via the VMware vMSC certification process, after which it is recognized with a unique hardware compatibility list category. All supported storage devices are listed in the VMware Storage Compatibility Guide.

What is Hitachi Virtual Storage Platform?

• Scale Up — Meet increasing demands by dynamically adding processors, connectivity, and capacity in a single unit. Provide the highest performance for both open and mainframe environments.
• Scale Out — Meet multiple demands by dynamically combining multiple units into a single logical system with shared resources. Support increased demand in virtualized server environments. Ensure safe multitenancy and quality of service through partitioning of cache and ports.
• Scale Deep — Extend storage value by virtualizing new and existing external storage systems dynamically. Extend the advanced functions of Hitachi Virtual Storage Platform to multivendor storage. Offload less-demanding data to external tiers to save costs and to optimize the availability of tier-1 resources.

Two VSP storage systems can be configured in a stretched metro cluster configuration by leveraging built-in features such as Hitachi High Availability Manager and Hitachi TrueCopy^® Remote Replication. This stretched configuration can provide service to 2 datacenters located within 300 kilometers of one another. Data volumes, including VMFS datastores, in this stretched configuration are highly available, and can be accessed by vSphere hosts on both sites simultaneously. In case of a site failure, the remaining data center VSP storage system continues to provide I/O access to the data volumes.

What are Hitachi High Availability Manager and the Hitachi Availability Manager Quorum Disk?

Built on the way VSP manages virtualized devices, Hitachi High Availability Manager administers internal storage and externally attached heterogeneous storage with common and integrated management. It is used in conjunction with Hitachi TrueCopy storage system-based replication technology, which synchronizes data between the designated primary copy, or P-VOL, and the remote secondary copy, or S-VOL.

Hitachi Dynamic Link Manager is multipathing software that integrates with Hitachi High Availability Manager (HAM) to provide load balancing and path failover capabilities for vSphere hosts (HDLM SATP and HDLM PSP). HDLM will load-balance I/O between all available paths from P-VOL and keep all paths to S-VOL as standby paths.

Configuration Requirements

These requirements must be satisfied to support this configuration:

• The round-trip latency between the Ethernet networks in the two sites must be less than 10 milliseconds (uniform host access). The IP network supports the VMware ESXi hosts and the VSP/HAM management interface.
• The round-trip latency for synchronous storage replication must be less than 5 milliseconds .
• The minimum throughput available between the two sites should be 622 Mbps, in order to support vMotion of virtual machines across ESXi hosts spread across both data centers.
• The ESXi hosts in both data centers must have a private network on the same IP subnet and broadcast domain.
• VMware vCenter Server must be accessible from all vSphere hosts on both sites.
• The same IP network on which the virtual machines reside must be accessible to ESXi hosts on both sites, so that clients accessing virtual machines running on ESXi hosts on both sites are able to function smoothly upon any VMware HA-triggered virtual machine restart event.
• The data storage locations, including the boot device used by the virtual machines, must be accessible from ESXi hosts in both data centers.
• The maximum number of vSphere hosts in the HA cluster must not exceed 32.
• Hitachi Dynamic Link Manager v7.2 or newer is required.
• Hitachi Virtual Storage Platform microcode v70.02 or newer is required.

Notes:

• The Hitachi Storage Cluster solution only supports uniform host access, meaning that the vSphere hosts at each site can access the VSP P-VOLs provisioned from the opposite site.

For any additional requirements for Hitachi Storage Cluster, see the Deploy VMware vSphere Metro Storage Cluster on Hitachi Virtual Storage Platform reference architecture document.

Solution Overview

A VMware vSphere Metro Storage Cluster architecture on Hitachi Virtual Storage Platform provides an ideal solution for maximizing availability and uptime by clustering physical data centers within metro distances. The metro storage cluster solution from Hitachi Data Systems consists of storage systems presenting replicated storage as a single LUN from different geographically distributed sites. This design enables high availability of services by allowing virtual machine migration between sites with no downtime.

A combination of Hitachi software and hardware provides the following key functions to a vSphere infrastructure:

• Host multipathing
• Internal and external storage provisioning
• Synchronous storage replication across metro cluster distances
• Storage failover

This solution uses a uniform host access configuration. In a uniform host access configuration, a primary datastore is synchronously replicated to a read-only secondary datastore. ESXi hosts from different sites can access the storage devices on both sites, but see the two LUNs as a single datastore.

• vSphere 5.0 ESXi hosts — The physical hosts on both data centers running the virtual machines and managed by vCenter Server
• Hitachi Virtual Storage Platform — High-performance and highly scalable storage solution
• Hitachi Unified Storage or existing Hitachi Adaptable Modular Storage or other supported 3rd-party storage systems — Midrange storage platform that provides reliable, flexible, scalable, and cost-effective modular storage, used by Hitachi High Availability Manager Quorum Disk
• Hitachi Dynamic Link Manager — Multipathing software that integrates with Hitachi High Availability Manager to provide load balancing and path failover capabilities for servers
• Hitachi TrueCopy® Remote Replication — Synchronous storage replication between storage systems
• Hitachi High Availability Manager — Storage failover coordination; allows hosts to see a pair of replicated LUNs as a single datastore
• Fibre Channel switch — SAN connectivity to the datacenter storage network
• Network switch — LAN connectivity to the datacenter network

Tested Scenarios