Turn off the node when replacement for SSD or HDD.

Hi,

If we read the following below, the node seems to be turned off when replacement for SSD or HDD through VxRail Manager. It will be very helpful if you let me know why the node is need to turned off for it?

・ From page 60. Replacing hardware

https://support.emc.com/docu70689_VxRail-Appliance-3.5-Product-Guide.pdf?language=en_US

Thanks.

Best regards,