ALUA is a standard used for identifying paths prioritization between the storage and hosts, and enables the initiators to query the target about path attributes, such as the paths ALUA state.
InfiniBox supported ALUA States
InfiniBox version 5 and above supports the following ALUA states:
- Active/Optimized: the optimal paths to serve I/O to the LUN.
- Active/Non-Optimized: performing I/O to the LUN is less optimal through these paths.
- Standby: paths in standby state cannot server reads or writes.
The host Active ALUA state (optimized/non-optimized) is settable on the InfiniBox Host object level. (storage side)
- By default, InfiniBox hosts are created as optimized.
- Means InfiniBox will set the ALUA paths state of all the volume to are mapped to that host to "Active/Optimized".
Note: the "Standby" state is not settable. InfiniBox will automatically change the ALUA state to Standby for peers that are not synchronized ("offline").
Host PowerTools and ALUA
Host PowerTools can display the host's Active ALUA state for each connected InfiniBox system, and provides the means to change this setting.
- Settings hosts ALUA state is available only on InfiniBox version 5.0 and above.
Setting the host's paths ALUA state
Host PowerTools allows to set the Active paths ALUA state of the hosts to “Optimized” or “Non-optimized” on each connected system.
- Settings the hosts's Active ALUA state applies only to the Active-Active volumes that are mapped to that host.
- The paths ALUA state of volumes that are not undergoing Active-Active replication is always "Active/Optimized".
- Setting the paths ALUA state to “Non-optimized” applies only to Active-Active volumes.
If the Active-Active replica is not synchronized:
One of the peers will become "offline" (not synchronized) and its ALUA state automatically changes to "Standby" by the InfiniBox system (the peer cannot serve reads or writes)
- The other peer stays "online".
- The ALUA state of an "online" peer while the Active-Active replica is not synchronized is always "Active/Optimized".
- When changing the ALUA state, it might take an additional short time for the operating system to discover the change.
- The operating system might override the ALUA state that is set on InfiniBox in some scenarios.
Setting through the CLI
- The command sets the host paths ALUA state to "Optimized" / "Non-Optimized" on the specified system.
Setting through the GUI
Open the main screen.
- Click on the desired "System drop list" and select "Settings".
Settings the paths ALUA state to 'Non-optimized' is recommended only if the host is mapped to active-active volumes where there is a better connection to the volumes via the other system.
Querying for the current Host ALUA state
Presents the current host ALUA state as set on each connected InfiniBox.
- Can be either "Optimized" or "Non-Optimized" per system.
- Note: if the host is not registered on a specific system, it will not be presented.
Querying through the CLI
Querying through the GUI
- Open the Host PowerTools main screen.
- Located on the desired system, click the More Options icon and select Settings.
- The default checked radio button presents the current host ALUA state.