The A3X00's and RSM 2000's need to be powered down and powered up in a specific order as not to cause a channel failure or loss of configuration.

It is imperative that whenever the need arises to power cycle an entire array, the following steps are followed.

1. Place the attached host system(s) at the ok prompt, if possible.
2. Power down the RDAC module (the part that contains the array's controllers).
3. Power down the disk trays.
4. Do whatever work is required on the array.
5. Power up the disk trays and leave them running for 30 seconds.
6. Power up the RDAC module.
7. Power up the host system.

If the RDAC module is powered on before the disks are spun up, you run the risk of the disks reporting themselves with a 'Replaced' status.