Access to your volume data can be lost if you incorrectly power off all or part of a system.
Use the management GUI or the CLI commands to power off a system. Using either of these methods ensures that the data that is cached in the node canister memory is correctly flushed to the RAID arrays.
Do not power off an enclosure unless instructed to do so. If you power off an expansion enclosure, you cannot read or write to the drives in that enclosure or to any other expansion enclosure that is attached to it from the SAS ports. Powering off an expansion enclosure can prevent the control enclosure from flushing all the data that it has cached to the RAID arrays.
Remove a node canister only when directed to do so by a service action. Physically removing an active node canister means that it is unable to write any configuration data or volume data that it has cached to its internal disk and the data is lost. If both node canisters in a control enclosure are removed in quick succession, run recovery actions, which might include restoring your volume data from a backup.