B: Updating Exadata Database Servers (compute nodes).
The software and firmware components that are updated for a specific release depend on the current Exadata software release the database server is running and the release you are updating to. Linux operating system packages and Exadata software are always updated while firmware may be updated for only a small selection of the components or not at all.
D: The storage cells (storage servers/nodes) contain HBAs, and spare PCI I/O slots.
References:
https://docs.oracle.com/cd/E41033_01/html/E55032/bbgiabie.html
http://docs.oracle.com/cd/E80920_01/DBMMN/updating-exadata-software.htm#DBMMN-GUID-AB25ED9A-7920-441A-9A60-14ED2753B01C

Explanation/Reference:
The exadcli utility runs commands on multiple remote nodes in parallel threads.
You can issue an ExaCLI command to be run on multiple remote nodes. Remote nodes are referenced by their host name or IP address. Unlike dcli, exadcli can only execute ExaCLI commands. Other commands, for example, shell commands, cannot be executed using exadcli.
References: http://docs.oracle.com/cd/E80920_01/DBMMN/exadcli.htm#DBMMN-GUID-4AE469A6-F291-
4737-B975-F1B4B91D0BA0

B: You can configure SNMP Trap Destinations for the Exadata Storage Servers with the following command:
# cellcli -e "alter cell snmpSubscriber=(host ='ASR-Manager-name-or-IP-address',port=162,community=public,type=asr)" D: Exadata Storage Server plug-in This extends the monitoring of exadata cells in addition to providing a GUI interface. The plug-in uses an SSH connection to the cellmonitor user on the cells and uses list commands only. This is for interactive monitoring. One may also set thresholds using the plug-in which are distinct from any thresholds set using cellcli utility as the celladmin user. For alerts to be sent to the plug-in, SNMP traps are used as follows:
Cell ILOM alerts are sent to the cell Management Server (MS) via an SNMP trap. The MS then send SNMP notifications onward to the plug-in.
Cell alerts flagged by MS itself, such as cell thresholds being exceeded, or ADR software alerts, are sent to the plug-in using SNMP.
E: Database Server ILOM plug-in
Monitoring databases and their instances, ASM environments, the Grid Infrastructure, and the host software environment are done by Enterprise Manager in the usual way as these are standard targets. But monitoring the hardware for the database servers requires the ILOM plug-in, as there is no Management Server (MS) on the database servers to receive SNMP traps from the ILOM. The plug-in will receive sensor state and availability data from the ILOM including alerts based on pre-set ILOM thresholds.
References:
https://dbatrain.wordpress.com/2011/06/
http://docs.oracle.com/cd/E21659_01/html/E21660/z40015671004046509.html

D: Whenever data blocks change, the Change Tracking Writer (CTWR) background process tracks the changed blocks in a private area of memory.
When RMAN performs an incremental backup on the Exadata platform, cellsrv filters out unwanted blocks and sends back only those that have changed since the last level 0 or level 1 backup.
E: For the Exadata platform, you may choose to allow cellserv to do all the blocking filtering for incremental backups.
Note: RMAN block change tracking is used to improve the performance of incremental backup. The level 0 incremental backup scans the entire database but level 1 incremental backups use the block change tracking file to scan only the blocks that have changed since the last backup. This significantly reduces the amount of reads that are required on the database.
References: Expert Oracle Exadata (29 Aug 2015), page 319

Explanation/Reference:
C: ILOM supports the Intelligent Platform Management Interface (IPMI), which enables you to monitor and control your server platform, as well as to retrieve information about your server platform.
ILOM supports alerts in the form of IPMI Platform Event Trap (PET) alerts. Alerts provide advance warning of possible system failures.
E: Oracle ILOM supports the Simple Network Management Protocol (SNMP), which is used to exchange data about network activity.
SNMP functionality requires the following two components:
Network management station - A network management station hosts management applications, which

monitor and control managed nodes.
Managed node - A managed node is a device such as a server, router, or hub that hosts SNMP

management agents that are responsible for carrying out requests from management stations, such as a service processor (SP) running Oracle ILOM. Managed nodes can also provide unsolicited status information to a management station in the form of a trap.
References: https://docs.oracle.com/cd/E19860-01/E21452/E21452.pdf