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Online Data Mobility (ODM) enables non-disruptive workloads movement between InfiniBox systems without any downtime.

  • The ODM process is integrated and manged using Host PowerTools.

Terminology

  • "Source" - describes the entity (system / volume / pool) which the data is moving from.
  • "Target" - describes the entity (system / volume / pool) which the data is moving to.

Usage

It is recommended to use ODM only in order to non-disruptively move workloads to a new InfiniBox system.

Online Data Mobility Process - High Level

The online data mobility is a process that is initiated and managed from within the hosts using Host PowerTools.

  • InfiniBox GUI or InfiniShell cannot manage the online data mobility process, however allow to query for mobility replicas which provides indication of the progress status. 

Mobility using Host PowerTools

Host PowerTools can perform online data mobility for volumes that are provisioned to the host on which it is running. 

  • The mobility process is driven by a set of "Mobility Operations".

Mobility through Host PowerTools simplifies the process and provides:

  • Best practices and configuration validation.
  • Storage and host automation.
  • Avoiding human errors.

Mobility Replica

The "Mobility" replica type is used to replicate the data from the source the target system. 

  • Mobility replicas behavior and states are identical to an Active-Active replica.
    • The source volume is set as the preferred.
  • The initial replica state of source-volumes undergoing mobility is "Sync in Progress". 
    • Data is asynchronously replicating to the target system. 
  • When the replica state transitions to "Synchronized" the volume is ready to complete the mobility process. 
    • While in "Synchronized" state, the source and target volumes are in an "Active-Active" relationship - new writes are distributed and acknowledged by both source and target systems.

Mobility Process

  • The entire process can be performed using two mobility operations - Initiate and Cut-over.
    • Initiate: Starts the mobility process
    • Cut-over: completes the mobility process.
  • Mobility is performed at the volume granularity - it supports mobility of all mapped volumes at once or in parts. 

The Process - High Level

  1. Login to the desired host and start the mobility process using Host PowerTools by running the "Mobility Initiate" operation command.
    • It's possible to state specific volume(s) or to state the source system in order to initiate the process on all volumes that are mapped from that system at once. 
    1. The environment configuration and best practices will be validated.
      • Upon success the mobility process is initiated:
        1. Identical entities (hosts / cluster / volumes) are provisioned on the target system.
        2. Mobility replica is created for each volume.
  2. Wait for the mobility replica/s state to become "Synchronized".
    • The mobility replica state can be monitored using the "Mobility list" command.
      Once the mobility replica state is "Synchronized", the process can be completed. 
  3. Complete the mobility process by running the "Mobility Cut-over" operation on the synchronized volumes.

    • All volumes with a synchronized replica state can cut-over at once or in parts.

    • After performing cut-over, the volume/s will be presented from target system only.

    • The operation can also perform a clean-up of the source entities. 

Clusters

The mobility process of volumes that are mapped to a clusters is similar and performed through one of the cluster's hosts.

General Prerequisites

  • The host OS is supported for Online Data Mobility. 
    • For the complete list see section "Supported Devices and OS" below.
  • The source and target systems should run InfiniBox version 5 or later.
  • The source and target systems are linked.
    • The link must support Active-Active replication. (a link with witness configured)
      • It is not mandatory to have an active witness. (for mobility purposes only, a witness can be configured using a non-existing IP such as "0.0.0.0")
  • The host / cluster is zoned to the target system. 
  • Host PowerTools version 5 and above is installed on the host from which the mobility process is initiated. 
    • The host must have network access the source and target systems on port 80/443.
    • InfiniBox Admin / Pool admin credentials are required. 
  • The application must leverage the OS native multipath software in order to allow a non-disruptive movement to the target system.

Qualified volumes for mobility

In order for a volume to be valid for online data mobility, it needs to meet the following requirements:

  • The volume is not already replicated.  
  • The volume is not a member of a consistency group. 
  • The volume is not mapped to more than one host or a cluster. 
  • The volume name does not exist on the target system. 
  • The volume is mapped through FC only.
  • The volume is not a snapshot.
  • The volume has a multipath device configured.

Supported Devices and OS

Online Data Mobility is not supported with the following Devices and operating systems:

  • Solaris 10 OS.
  • Windows 2008 and 2008R2.
  • Boot-from-SAN volumes (devices) of Solaris 11 OS.
  • Boot-from-SAN volumes (devices) of RHEL 5.11 OS.

Online Data Mobility is supported with for all the rest of the operating systems and devices which are supported by HPT.

Limitation

  • Mobility of the volume's snapshots tree to the target system is not supported. 

Zoning Best Practices 

It is recommended to have each host zoned to the target and source systems with one path to each InfiniBox node from two initiators. (exactly 6 paths to each system)

Supported Distance between the Source and Target systems

Online Data Mobility is supported across the allowed distance of InfiniBox sync replication - up to 5ms RTT.

  • However, it is recommended to perform online data mobility between systems within the same datacenter.
    • When the mobility replica is "Synchronized" (Active-Active relationship), an approximately 400 micro-sec latency is added to write operations, if the two systems are in the same datacenter network. 

Boot from SAN 

  • Online data mobility is supported also for volumes which are used for boot from SAN. (hosts that boot from an InfiniBox volume)
  • After the mobility process is completed, the host boot BIOS must be updated to point the target volume (on the target system), so when the host is rebooted at a later time it will be able to find the volume that contains the operating system.

Before performing Online Data Mobility on Boot-from-SAN volumes, ensure that the OS boot-disk leverages the OS native multipath software in order to allow a non-disruptive movement to the target system.

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