Deploying a Metro Storage Cluster across two sites using Huawei OceanStor Hybrid Flash Storage HyperMetro and VMware vSphere
Article ID: 311896
Updated On:
Products
VMware vSphere ESXi
Issue/Introduction
This article describes the uniform and non-uniform topology for using Huawei HyperMetro of OceanStor Hybrid Flash Storage with the VMware vSphere HA cluster, and provides information about deploying a Metro Storage Cluster across two sites using Huawei HyperMetro and VMware vSphere.
Environment
VMware vSphere ESXi 5.1
Resolution
What is Huawei OceanStor Hybrid Flash Storage?
Huawei OceanStor new-generation hybrid flash storage are products designed for all-flash data centers.
Designed to help users achieve their business goals, they adopt new algorithms for all-flash storage to improve SSD utilization and performance. Their comprehensive convergence and value-added features deliver leading system efficiency and reliability, while the built-in Insight module provides intelligent prediction. The systems supercharged by the features provide diversified storage services to users, ideal for the finance, government, manufacturing, education, healthcare, energy, and media entertainment sectors.
HyperMetro delivers the active-active service capabilities based on two storage arrays. Data on the active-active LUNs at both ends is synchronized in real time, and both ends process read and write I/Os from application servers to provide the servers with non-differentiated parallel active-active access.
What is HyperMetro?
HyperMetro is Huawei's active-active storage solution that enables two storage systems to process services simultaneously, establishing a mutual backup relationship between them. If one storage system malfunctions, the other one will automatically take over services without data loss or interruption. With HyperMetro being deployed, you do not need to worry about your storage systems' inability to automatically switch over services between them and will enjoy rock-solid reliability, enhanced service continuity, and higher storage resource utilization. HyperMetro supports both single-data center (DC) and cross-DC deployment modes.
Dual-write ensures data redundancy on the storage systems. In the event of a storage system or DC failure, services are switched over to the other DC at zero RTO and RPO, ensuring service continuity without any data loss.
Minimum Requirements:
These are the minimum system requirements for a vMSC solution with HyperMetro:
• Huawei OceanStor Hybrid Flash Storage 6.1 or newer
• Huawei OceanStor Hybrid Flash Storage should be connected with ESXi via FC, FC-NVME, NVMe over RoCE or iSCSI.
• ESXi 5.1 and later.
• Huawei UltraPath, VMware HPP or VMware NMP.
• vSphere 7.0 or later support FC-NVME and NVMe over RoCE
Solution Overview:
The VMSC solution supports both uniform access (cross-connected networking) and non-uniform access (parallel networking), depending on how the host accesses the storage system. This chapter describes the differences between the two access methods to help customers choose one that best suits their networks.
Uniform Access (recommended)
Uniform access means that ESXi hosts at each site are connected to both the local and remote storage systems. Any ESXi host has the paths to access both the local and remote storage systems at the same time.
Figure 1 Uniform access network
In the preceding figure, host A at site 1 and host B at site 2 have links to both OceanStor A and OceanStor B, and there are replication links between OceanStor A and OceanStor B. If site 1 and site 2 are deployed in the same equipment room, the hosts at both sites reach the storage systems at a similar latency. If site 1 and site 2 are in different equipment rooms in the same metropolitan area, the latency for a host to access its local storage system is shorter than that for the host to the remote storage system because the links introduce extra latency. To achieve the optimal performance of active-active storage systems, avoid using the paths to the remote storage system unless absolutely necessary.
If VM 1A sends a write request to volume A on OceanStor B, an extra latency equivalent to 2-fold the round-trip time (RTT) on the replication link between the storage systems will be added to the write latency. The write request must be sent from host A to OceanStor B, and then OceanStor B synchronizes the write request to OceanStor A. If the RTT of the replication link is 3 ms, this process increases the write latency by 6 ms, which is unacceptable to enterprises' mission-critical applications.
OceanStor Hybrid Flash Storage HyperMetro supports ALUA. When a host delivers a command to query paths, the storage system reports the Active/Optimized (AO) and Active/Non-Optimized (AN) paths. For HyperMetro in the same equipment room, Huawei UltraPath can set a load balancing policy, which configures all paths from the host to both storage systems as AO paths. I/Os are delivered to all of the paths in a round-robin way. For HyperMetro across two equipment rooms over distance, UltraPath sets the paths to the local storage system as AO paths and those to the remote storage system as AN paths. The host preferentially uses the AO paths for reads and writes, and uses the AN paths only when the local storage system is faulty. This is also the case when the host's Native Multipathing Plug-In (NMP) is used. OceanStor Hybrid Flash Storage provides configuration items on DeviceManager to set the load balancing or local preference policy. By using the multipathing settings, the extra latency introduced by the replication link is avoided.
Non-Uniform Access
Non-uniform access means that ESXi hosts at each site are connected only to the local storage system. Any ESXi host can access only its local storage system.
Figure 2 Non-Uniform access network
In the preceding figure, host A at site 1 only has links to OceanStor A, and host B at site 2 only has links to OceanStor B. Therefore, VMs on host A can only access OceanStor A, and VMs on host B can only access OceanStor B. The multipathing software can only identify paths to the local storage system, and all of the paths are Active/Optimized (AO) paths.
In HyperMetro configurations:
Arbitration server:
HyperMetro supports arbitration by pair or by consistency group. In the event of link or other failures, HyperMetro provides two arbitration modes:
• The operating system’s support matrix with Huawei storage, please visit http://support-open.huawei.com/en/ for more details.
Huawei OceanStor new-generation hybrid flash storage are products designed for all-flash data centers.
Designed to help users achieve their business goals, they adopt new algorithms for all-flash storage to improve SSD utilization and performance. Their comprehensive convergence and value-added features deliver leading system efficiency and reliability, while the built-in Insight module provides intelligent prediction. The systems supercharged by the features provide diversified storage services to users, ideal for the finance, government, manufacturing, education, healthcare, energy, and media entertainment sectors.
HyperMetro delivers the active-active service capabilities based on two storage arrays. Data on the active-active LUNs at both ends is synchronized in real time, and both ends process read and write I/Os from application servers to provide the servers with non-differentiated parallel active-active access.
What is HyperMetro?
HyperMetro is Huawei's active-active storage solution that enables two storage systems to process services simultaneously, establishing a mutual backup relationship between them. If one storage system malfunctions, the other one will automatically take over services without data loss or interruption. With HyperMetro being deployed, you do not need to worry about your storage systems' inability to automatically switch over services between them and will enjoy rock-solid reliability, enhanced service continuity, and higher storage resource utilization. HyperMetro supports both single-data center (DC) and cross-DC deployment modes.
Dual-write ensures data redundancy on the storage systems. In the event of a storage system or DC failure, services are switched over to the other DC at zero RTO and RPO, ensuring service continuity without any data loss.
Minimum Requirements:
These are the minimum system requirements for a vMSC solution with HyperMetro:
• Huawei OceanStor Hybrid Flash Storage 6.1 or newer
• Huawei OceanStor Hybrid Flash Storage should be connected with ESXi via FC, FC-NVME, NVMe over RoCE or iSCSI.
• ESXi 5.1 and later.
• Huawei UltraPath, VMware HPP or VMware NMP.
• vSphere 7.0 or later support FC-NVME and NVMe over RoCE
Solution Overview:
The VMSC solution supports both uniform access (cross-connected networking) and non-uniform access (parallel networking), depending on how the host accesses the storage system. This chapter describes the differences between the two access methods to help customers choose one that best suits their networks.
Uniform Access (recommended)
Uniform access means that ESXi hosts at each site are connected to both the local and remote storage systems. Any ESXi host has the paths to access both the local and remote storage systems at the same time.
Figure 1 Uniform access network
In the preceding figure, host A at site 1 and host B at site 2 have links to both OceanStor A and OceanStor B, and there are replication links between OceanStor A and OceanStor B. If site 1 and site 2 are deployed in the same equipment room, the hosts at both sites reach the storage systems at a similar latency. If site 1 and site 2 are in different equipment rooms in the same metropolitan area, the latency for a host to access its local storage system is shorter than that for the host to the remote storage system because the links introduce extra latency. To achieve the optimal performance of active-active storage systems, avoid using the paths to the remote storage system unless absolutely necessary.
If VM 1A sends a write request to volume A on OceanStor B, an extra latency equivalent to 2-fold the round-trip time (RTT) on the replication link between the storage systems will be added to the write latency. The write request must be sent from host A to OceanStor B, and then OceanStor B synchronizes the write request to OceanStor A. If the RTT of the replication link is 3 ms, this process increases the write latency by 6 ms, which is unacceptable to enterprises' mission-critical applications.
OceanStor Hybrid Flash Storage HyperMetro supports ALUA. When a host delivers a command to query paths, the storage system reports the Active/Optimized (AO) and Active/Non-Optimized (AN) paths. For HyperMetro in the same equipment room, Huawei UltraPath can set a load balancing policy, which configures all paths from the host to both storage systems as AO paths. I/Os are delivered to all of the paths in a round-robin way. For HyperMetro across two equipment rooms over distance, UltraPath sets the paths to the local storage system as AO paths and those to the remote storage system as AN paths. The host preferentially uses the AO paths for reads and writes, and uses the AN paths only when the local storage system is faulty. This is also the case when the host's Native Multipathing Plug-In (NMP) is used. OceanStor Hybrid Flash Storage provides configuration items on DeviceManager to set the load balancing or local preference policy. By using the multipathing settings, the extra latency introduced by the replication link is avoided.
Non-Uniform Access
Non-uniform access means that ESXi hosts at each site are connected only to the local storage system. Any ESXi host can access only its local storage system.
Figure 2 Non-Uniform access network
In the preceding figure, host A at site 1 only has links to OceanStor A, and host B at site 2 only has links to OceanStor B. Therefore, VMs on host A can only access OceanStor A, and VMs on host B can only access OceanStor B. The multipathing software can only identify paths to the local storage system, and all of the paths are Active/Optimized (AO) paths.
In HyperMetro configurations:
- Two devices on OceanStor Hybrid Flash Storages are both Read/Write accessible to hosts.
- Hosts could read/write to both devices in a HyperMetro Pair.
- Two devices in a HyperMetro Pair share the same external device identity (geometry, device WWN).
Arbitration server:
HyperMetro supports arbitration by pair or by consistency group. In the event of link or other failures, HyperMetro provides two arbitration modes:
- Static priority mode: This mode is mainly used in scenarios where no third-party arbitration servers are deployed. In this mode, you can set either end as the preferred site based on active-active pairs or consistency groups and the other end the non-preferred site.
If the link between the storage arrays or the non-preferred site encounters a fault, LUNs at the preferred site are accessible, and those at the non-preferred site are inaccessible.
If the preferred site encounters a fault, the non-preferred site is not accessible to hosts.
- Arbitration server mode: In this mode, an independent physical or virtual machine is used as the arbitration device, which determines the type of failure, and uses the information to choose one side of the device pair to remain R/W accessible to the host. The Arbitration server mode is the default option.
• The operating system’s support matrix with Huawei storage, please visit http://support-open.huawei.com/en/ for more details.
- Arbitration server could be built on a physical or virtual machine.
Recommendations and Limitations:
For LUNs that are shared among multiple hosts, make sure that host LUN IDs are consistent across all hosts (Setting LUN Allocations).
When using VMware NMP, it is recommended to upgrade to ESXi 6.0 U2 for ESXi 6.0 version. Please refer to this VMware KB article: Storage PDL responses may not trigger path failover in vSphere 6.0 (2144657).
It’s also recommended that the user mapping the LUN_2 device to ESXi host only after the Pair is success configured. User can use the rescan command to detect the new path, paths are detected automatically by UltraPath or VMware NMP. There might be some delay in automatic detection. Please refer to this VMware KB article for instructions on updating this tunable: Changing the polling time for datastore paths (1004378).
For more in depth information of HyperMetro, see the technical notes on Huawei Support.
A certified configuration of OceanStor Hybrid Flash Storage is available, and is listed in the VMware Compatibility Guide.
Tested Scenarios:
This table outlines the tested and supported failure scenarios when using a Huawei OceanStor Hybrid Flash Storage Cluster for VMware vSphere:
For LUNs that are shared among multiple hosts, make sure that host LUN IDs are consistent across all hosts (Setting LUN Allocations).
When using VMware NMP, it is recommended to upgrade to ESXi 6.0 U2 for ESXi 6.0 version. Please refer to this VMware KB article: Storage PDL responses may not trigger path failover in vSphere 6.0 (2144657).
It’s also recommended that the user mapping the LUN_2 device to ESXi host only after the Pair is success configured. User can use the rescan command to detect the new path, paths are detected automatically by UltraPath or VMware NMP. There might be some delay in automatic detection. Please refer to this VMware KB article for instructions on updating this tunable: Changing the polling time for datastore paths (1004378).
For more in depth information of HyperMetro, see the technical notes on Huawei Support.
A certified configuration of OceanStor Hybrid Flash Storage is available, and is listed in the VMware Compatibility Guide.
Tested Scenarios:
This table outlines the tested and supported failure scenarios when using a Huawei OceanStor Hybrid Flash Storage Cluster for VMware vSphere:
| Scenario | Operation | Observed VMware behavior (uniform) | Observed VMware behavior (non-uniform) |
| Cross-data-center VM migration | Migrate a VM from site A to site B. | No impact. | No impact. |
| Physical server breakdown | Unplug the power supply for a host in site A. | VMware High Availability failover virtual machines to other available hosts. | VMware High Availability failover virtual machines to other available hosts. |
| Single-link failure of physical server | Unplug the physical link that connects a host in site A to an FC switch. | No impact. | No impact. |
| Storage failure in site A | Unplug the power supply for the storage system in site A. | No impact. | VMware High Availability failover virtual machines to available site B hosts. |
| All-link failure of storage in site A | Unplug all service links that connect site A's storage array to an FC switch. | No impact. | VMware High Availability failover virtual machines to available site B hosts. |
| All-link failure of all hosts in site A | Unplug all physical links that connect all hosts in site A to an FC switch. | VMware High Availability failover virtual machines to available site B hosts. | VMware High Availability failover virtual machines to available site B hosts. |
| Failure of storage replication links | Unplug replication links between sites. | No impact. | Virtual machines in site B hosts are automatically Powered off in site B hosts and Powered on in available site A hosts.(ps: The perfect site is site A) |
| Failure of storage management network | Unplug network cable from network port of host in site A. | No impact. | No impact. |
| All-link failure between sites | Disconnect the DWDM links between sites. | Virtual machines in site B hosts are automatically Powered off in site B hosts and Powered on in available site A hosts.(ps: The perfect site is site A) | Virtual machines in site B hosts are automatically Powered off in site B hosts and Powered on in available site A hosts.(ps: The perfect site is site A) |
| Failure of site A | Power off all devices in site A. | VMware High Availability failover virtual machines to available site B hosts. | VMware High Availability failover virtual machines to available site B hosts. |
| Failure of site B | Power off all devices in site B. | VMware High Availability failover virtual machines to available site A hosts. | VMware High Availability failover virtual machines to available site A hosts. |
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