3.4 Flashcards
Resiliency, capacity planning, recovery testing, backups, power resiliency
What is the difficulty with maintaining HA?
It is very high cost. There is always another contingency you can add. Upgraded power, high-quality server components… it never ends.
A resiliency method of combining two or more servers to act as a single large server. This works in such a way that users only see one device.
This is used to increase capacity and availability.
Server clustering
True/False
Clustered servers typically use different OSs
False
Clustered servers commonly use the same OS. This enables interoperability.
True/False
Clustered servers do not write directly to their own storage systems.
True
Clustered servers typically write to a single shared storage directory. This ensures that every server has up-to-date information when they perform operations.
A resiliency method of placing a central device between the network and a collection of servers. This central device directs traffic to each server in a way that is most efficient for performance and availability.
In this configuration, each server is not aware of the other servers’ presence.
Load balancing
A recovery site that is an exact replica of an organization’s datacenter. This includes hardware, software, patches, updates, and data.
Hot site
A recovery site that provides an empty building for an organization to move into. They must then purchase and install hardware, software, and then download up-to-date proprietary data. They must then move over the team members to this site before it can work.
Cold site
A recovery site that may have some hardware, software, and data available, but may need additional installations and configuration to be up and running.
Warm site
True/False
Your recovery site should be close to your main site, so that it is easier to move to it if in need.
False
If disaster is caused by an act of God, the alternate site may also be affected. It is best to have the other site in a different geographic location to avoid this.
True/False
It is best to use the same OS for all of your organization’s devices because it makes interoperability easier.
False
Using a single OS can pose a security risk since vulnerabilities are very well documented online. By using many different OSs, it prevents one vulnerability from causing a problem in the entire network.
True/False
It is best to use one cloud provider to eliminate the security risks associated with using multiple clouds.
False
Using multiple cloud providers can provide resiliency and security. That way, your data is both geographically and cloud service dispersed. A breach or outage with one provider wouldn’t affect the others.
COOP stands for
Continuity of Operations Planning
What is a COOP used for?
When disasters come and you need to find a solution to continue operations.
These alternative could be manual rather than digital; paper receipts instead of automated receipts, manual transactions instead of card transactions, and phone calls.
A method of incident response training where the team responsible talk through a simulated disaster/drill in order to practice their response.
Tabletop exercise
A recovery method where, when the primary system fails, a secondary, redundant system takes on the load.
Failover
A method where multiple devices or CPUs are used to process transactions. It could be a single device with multiple CPU cores, or multiple computers.
It provides resiliency since if one of those processors fails, the other processors can take on the load.
This also improves performance since transactions are spread throughout multiple processors instead of just one.
Parallel processing
A backup that is immediately available because it is at the same location as the organization.
Onsite backup
A backup that needs to be transferred over the internet over a WAN link or shipped because it is not in the same location as the organization. To use it for recovery, you must be network connected to it.
Offsite backup
True/False
Most organizations use both onsite and offsite backups. Onsite for quick access, and offsite for long-term storage.
True
What is the most common way that backups are protected? This is especially useful for backups on the cloud.
Encryption
A common type of backup used for VMs and cloud-based infrastructures. It is an instant backup of an entire system - configuration and data included. Each backup after the original one contains only the changes between them.
Snapshot
Which type of backup is similar to an incremental backup?
Snapshot
Once the original snapshot is taken, any snapshots following contain only the changes made.
A test used to make sure that the backups are not corrupted and can be recovered from quickly. This includes a complete restoration from the backup and testing on every application to make sure everything works properly.
Recovery test
An ongoing, almost real-time backup that keeps data synchronized in multiple locations. Commonly used to prepare a hot site.
Replication
A technology that writes changes that should be made to a separate intermediate file. After that file gets written to, then the changes are made.
This prevents corruption due to power outage. If the power goes out while the intermediate file is written, the data is simply lost.
If the power goes out while the changes are being made, instead of the data getting corrupted, the computer instead looks to that intermediate file for the correct version of data and updates itself to match it.
Journaling
UPS stands for
Uninterruptable Power Supply
UPS is good for ____ backup power
Short-term (a few hours)
Generators are good for ____ backup power.
Long-term
A UPS that is constantly running on main power. When the main power fails, a switch pulls where it changes from the main power to battery backup.
Offline/standby UPS
A type of UPS that can increase the voltage if you see a decrease in the powerline. (Mitigates brownouts)
Line-interactive UPS
A type of UPS that completely isolates the equipment from raw utility power. The equipment instead runs on this type of UPS 24/7, and there is zero transfer time to the battery power.
Online/double-conversion UPS
True/False
Generators have a higher capacity than UPSs
True
UPSs have limits on what they can do, while generators can power entire buildings.
How are UPSs and generators often used together?
Generators take a while to get started, so using a UPS in the meantime helps make an uninterrupted power supply.
