In previous versions, ZStack Cloud has provided memory reclaim and sharing mechanisms that help ensure the efficient use of host memory through memory dynamic allocation and de-duplication.

Starting from 5.1.0, ZStack Cloud further enhances the memory reclaim and sharing mechanisms, making the mechanisms can take effect in a finer granularity and providing a more intuitive monitoring to displays the host memory changes.

Allows You to Enable/Disable Memory Balloon and Kernel Same-Page Merging for an individual VM Instance

• Memory Balloon: The setting called Memory Reclaim in previous versions is renamed as Memory Balloon in 5.1.0. This mechanism monitors the host and VM memory utilization in real-time and ensures a high host memory use efficient by allocating/reclaiming memory to/from VM instances dynamically.
  • Reclaim: If the VM workloads decreases, a part of its free memory is reclaimed to the host when the host memory utilization is higher than 80%. The reclaimed memory can be allocated to those VM instances with increasing workloads.
  • Allocate: If the VM workloads increases, the host allocates more memory to it to ensure the business stability.
• Kernel Same-Page Merging: A mechanism realizing the host memory sharing. This mechanism scans the VM memory page periodically, detecting whether multiple VM memory pages are mapped to physical memory pages with identical content and re-mapping these VM memory pages to one physical memory page. This allows multiple VM instances to share host memory and reduce resource wastes.

The two mechanisms mentioned above ensure a high use efficient of host memory. However, for VM instances that are running important businesses, these mechanisms may bring a performance influence. Starting from 5.1.0, you can enable/disable Memory Balloon or Kernel Same-Page Merging for a VM instance individually on its action list or details page. VM instances with Memory Balloon and Kernel Same-Page Merging disabled can enjoy more dedicated and stable memory spaces.

You can enable/disable these two mechanisms flexibly for different VM instances according to your business requirements, improving the physical memory use efficient as well as ensuing the stability of your core businesses.

Provides a Host Memory Monitoring that Displays the Memory Reclaimed/Shared/Saved in a more Intuitive Way

Starting from ZStack Cloud 5.1.0, you can view the host memory reclaimed/shared/saved through the Memory Balloon and Kernel Same-Page merging mechanisms in a more intuitive way on the host details page. The following metrics are displayed on the monitoring dashboard (Memory Reclaim):

• Reclaimed through Memory Balloon: Displays the memory size reclaimed from VM instances with decreasing workloads.
• Shared by VM Instances: Displays the memory size that is shared by multiple VM instances because of the Kernel Same-Page Merging mechanism.
• Economized through KSM: Displays the memory size saved because of the Kernel Same-Page Merging mechanism.

ZStack Cloud 5.1.0 improves the NeverStop HA mode, making it triggers an auto VM reboot only when the VM instance is stopped unexpectedly. If the VM instance is stopped manually or through a scheduled job, it does not automatically reboot even though its HA mode is set as NeverStop.

Starting from ZStack Cloud 5.1.0, when you perform a Change Primary Storage or Change Host and Primary Storage operation on VM instances, you can now specify the Total Migration Rate. The system limits the maximum I/O read rate of the VM instance and its attached volumes in the source primary storage. In this way, you can proactively manage and control the migration process, reducing I/O contention due to large-scale data migration and lowering the impact on business.

In previous versions, before hot migrating a VM instance with VF NICs attached, you need to manually detach the VF NICs. Starting from ZStack Cloud 5.1.0, you can now hot migrate VF NIC VM instances with one click to achieve an consistent experience with vNIC VM instances and realize seamless migration.

Starting from ZStack Cloud 5.1.0, you can make elastic baremetal instances connected with new-generation high-performance distributed storage by attaching block storage volumes to them. Then, the elastic baremetal instances can enjoy a lower-latency and higher-performance storage service.

In addition, the multiplepath has been configured by default, effectively avoiding single-point failure of data reading/writing and better ensures the data security.

Starting from ZStack Cloud 5.1.0, when you perform a Change Host and Primary Storage operation on a VM instance that uses LocalStorage, you can hot migrate the VM instance (and all volumes attached to it, if any) across LocalStorage.

ZStack Cloud 5.1.0 makes the following enhancements on load balancer.

Adds Support for IPv6 Protocol in LB, Improving Network Performance and Security

ZStack Cloud 5.1.0 adds support for IPv6 protocol in load balancing service, allowing traffic forwarding between multiple IP protocols to meet diverse business needs.

	Frontend Network	Backend Network
Protocol Forwarding	IPv4	IPv4
	IPv4	IPv6
	IPv6	IPv4
	IPv6	IPv6
	IPv4+IPv6 Dual Stack	IPv4
	IPv4+IPv6 Dual Stack	IPv6

Starting from 5.1.0, ZStack Cloud provides a new network service, shared bandwidth. A shared bandwidth can be used by multiple public network VIPs and limits the total speed of these VIPs centrally.

Public VIPs are important methods for VM instances on VPC networks to access the public network. For example, you can create EIPs based on public network VIPs and attach the EIPs to VM instances on the VPC network. Then, the VM instances can communicate with the public network through these public network VIPs. If these VIPs are bound to the same shared bandwidth, then, these VM instances can share the same bandwidth and be limited on speed centrally when they access the public network, which helps you reduce the cost on the public network communications.

Starting from ZStack Cloud 5.1.0, you can modify the type and VLAN ID/VNI of a L2 network on its details page, providing a more flexible network O&M service.

Currently, the following modifications are supported:

• Changing an L2NoVlanNetwork to an L2VlanNetwork.
• Changing an L2VlanNetwork to an L2NoVlanNetwork.
• Modifying the VLAN ID of an L2VlanNetwork.
• Modifying the VNI of a VxlanNetwork.

Note: You cannot modify the L2 network type and VLAN ID/VNI if the L2 network has a management/flow network attached, or has a baremetal/elastic baremetal cluster attached, or has configured with a SR-IOV/Smart NIC network acceleration mode, or has PVLAN (Isolated) enabled.

Starting from ZStack Cloud 5.1.0, 223.5.5.5 is no longer used as the default DNS address of public and flat networks. If you do not manually specify a DNS address for a public/flat network, the system does not configure a DNS service for this network automatically.

In previous versions, ZStack Cloud has supported SNMP management, allowing you to obtain Cloud resource monitoring data on a third-party platform through SNMP (Simple Network Management Protocol). In the previous version, you can obtain only the monitoring data of hosts on the Cloud through SNMP.

Starting from ZStack Cloud 5.1.0, SNMP supports more metrics. You can obtain the monitoring data of more resources on the Cloud through SNMP, including primary storage, backup storage, VM instances, and VPC vRouters.

Starting from ZStack Cloud 5.1.0, new information items, Job Description and Trigger Reason, are added to the HA log and auto-scheduling log main lists. If you click Job Description, a log details page is displayed to provide more log details. You can quickly find why a HA or auto-scheduling job is triggered on the log list or details page, which makes the resource failure troubleshoot easier.

In previous versions, ZStack Cloud allows you to export data volume information as a CSV table which can be looked up conveniently offline. ZStack Cloud 5.1.0 makes the following improvements on the volume export.

Allows You to Export Information of Data Volumes and Root Volumes Simultaneously

The volume main list on ZStack Cloud displays data volumes only, but starting from ZStack Cloud 5.1.0, when you export volume on the volume main list, you can select the checkbox Export Root Volume Simultaneously to make the exported CSV file contain the information of root volumes that are associated with selected data volumes.

Note: You can select Export Root Volume Simultaneously only when you export volumes on the Available tab.

Allows You to Customize the Information Items to be Exported

Starting from ZStack Cloud 5.1.0, you can customize the information items that you want to be contained in the exported CSV file. This effectively the flexibility of the volume export.