OpenStor HA High Availability Storage Solution
VA Technologies and Nexenta are partnering to deliver Enterprise Class storage solutions with optional clustering capabilities based to deliver enterprise class performance at a fraction of the cost of proprietary solutions.

The OpenStor HA High Availability Storage Solution gives customers Enterprise Class features such as automatic failover of head nodes, virtually unlimited file system size, single namespace, integrated search features, block level real time mirroring and infinite snapshots for backup and for disaster recovery. The revolutionary ZFS file system at the heart of NexentaStor eliminates the growing risk of silent data corruption through an integrated approach that includes RAIDZ and RAIDZ2 as well as end to end checksum algorithms for every transaction that together identify and correct data corruption before it has a chance to proliferate through the storage system.

Nexenta HA Cluster Plugin
The HA Cluster plugin enables two NexentaStor instances to be configured as an active / active pair. When installed and configured, each instance of NexentaStor is able to perform all regular functions as per appliance's datasheet (User Guide document, Section "Data Sheet"), while at the same time along with another NexentaStor instance also providing high availability for shared storage accessible from both appliances.

The storage jointly managed via HA Cluster 1.0 configured is shared storage. You can also establish RAID and replication policies to protect the data itself in a number of ways with the aid of NexentaStor. The purpose of HA Cluster 1.0 is to eliminate as a single point of failure the NexentaStor instances themselves. In the future HA Cluster will support multiple instance protection schemes and also a broader set of configurable failure conditions. At launch, only two instances can be configured to failover for each other. Also, at launch the failure conditions that will cause a failover include lack of network connectivity and the server itself being powered down or otherwise becoming non responsive.

Heartbeats
At least one heartbeat must be transmitted to each member of a HA Cluster for control and monitoring requests to be propagated. HA Cluster 1.0 supports 3 types of heartbeat communication channels:

• Shared disk accessible and writeable from all appliances in the cluster (also sometimes called quorum device)
• Ethernet link
• Serial link

Appliances in the HA Cluster periodically synchronize, by exchanging their respective configurations. No manual intervention required - the respective configurations are continuously stored and backed up on-change, upon creation (and for the lifetime) of a HA Cluster.

NexentaStor's HA Cluster ensures service continuity in presence of service level exceptional events, including power outage, disk failures, appliance running out of memory or crashing, etc.

In its first release, the NexentaStor HA Cluster plugin provides the fundamental service of sharing given CIFS or NFS volumes. In the NexentaStor HA Cluster, a given shared volume will be accessible (and all its network shares will be available) even if one of the appliances goes down or becomes unresponsive.

Note that HA Cluster does establish a group of NexentaStor appliances, and therefore provides a superset of the corresponding NexentaStor "basic group" functionality that enables multi-system management. In particular, an end user can use the 'switch' command to switch any particular NexentaStor Management Console that is a member of the group to operate in a group mode - that is, execute console level commands on all appliances in the group (in this case - in the HA Cluster)

The NexentaStor management suite includes the NexentaStor Management View, which is a web-based GUI, the NexentaStor Management Console, which includes wizards and the ability to record and replay commands across all deployed NexentaStor instances, and the NexentaStor Storage API, which is a fully documented network based API.

Full Management and Reporting
The appliance comes with a number of standard pluggable modules that perform essential Fault Management, Performance Monitoring and Reporting functions.

• Memory and CPU utilization
• State and status of appliance's hardware, including physical disks
• State and status of appliance's services and facilities
• Storage services
• NFS statistics
• Network utilization reporting
• State and operational status of the Nexenta Management Server.