The power cables of the XtremIO X1 DAE (Disk Array Enclosure) for X-Brick 1 should be removed during an emergency shutdown procedure. This is a critical step to ensure the safety of the hardware and data integrity in the event of an emergency that requires immediate power down of the system.
The process typically involves:
Identifying the Emergency: Recognize the situation that necessitates an emergency shutdown, such as power surges, environmental hazards, or other immediate risks.
Initiating Emergency Shutdown: Engage the emergency shutdown procedure as outlined in the XtremIO documentation. This may involve using emergency power-off (EPO) switches or other mechanisms designed for rapid shutdown.
Disconnecting Power Cables: Once the system is safely powered down, disconnect the DAE power cables from X-Brick 1. This step helps prevent any electrical damage or data corruption that could occur if power is unexpectedly restored during the emergency.
Ensuring Safety: Verify that all power sources are disconnected and that it is safe to handle the cables and hardware.
Documenting the Procedure: Record the steps taken during the emergency shutdown, including the removal of power cables, to assist in any subsequent investigation or system recovery efforts.

When initializing a cluster for the first time with the create-cluster command on an XtremIO X2, the required parameter is the 'package'. This parameter specifies the software package that will be used to create the cluster. It is essential because it determines the version of the operating system and management software that will be installed on the cluster nodes.
The 'package' parameter is part of the command syntax and must be provided for the command to execute successfully. Without specifying the package, the command would not know which software to install, leading to an incomplete or failed initialization process.

In XtremIO, snapshots are created efficiently using metadata rather than duplicating the actual data blocks.
When a snapshot is made, it initially shares the same data blocks as its ancestor. When the first write occurs to a block in a snapshot, it triggers a Copy-On-First-Write (COFW) operation. This means the original data block is copied to a new location to preserve the integrity of the snapshot, ensuring that each snapshot reflects the data state at the moment of its creation.
This COFW operation ensures that the data remains consistent and unchanged for each snapshot, while allowing new writes to occur without impacting the original data or other snapshots. As a result, the first write to each snapshot impacts its ancestor by triggering a COFW operation.
References:
* Dell XtremIO Deployment and Learning Course Materials