3.4 Flashcards
network load balancer
a device that is used to evenly distribute incoming network traffic across multiple servers or resources when there is a high volume of traffic coming into the company’s network or web server
load balancer (info)
They distribute Transmission Control Protocol (TCP),
User Datagram Protocol (UDP), Hypertext Transfer
Protocol (HTTP), and Transport Layer Security (TLS)
traffic across multiple servers to efficiently allocate
resources and offer failover solutions
clustering
intended to improve performance and availability of a complex physical or virtual system
involves an active node and a passive node that share a common quorum disk, reinforced by a witness server, heartbeat communication and a VIP at the forefront
Clusters are designed to be a redundant set of service functionalities based on active-standby or active-active deployments
Cluster deployments are often measured by:
- Reliability – the ability to successfully provide responses on each incoming request
- Availability – the uptime of the server (usually measured as % of annual uptime)
- Performance the average of the time spent by the service to provide responses or by the throughput
- Scalability – the ability to handle a growing amount of work in a capable manner without degradation in the quality of service
clustering techniques
High availability clusters
Load balancing clusters
High-performance clusters
Storage clusters
High availability clusters
prioritize resilience over
other advantages and can be implemented in either
Active-Passive or Active-Active architecture
Load balancing clusters
highlight balancing the jobs
among all of the servers in the cluster and incorporate load balancing software in the controller node
High-performance clusters
use multiple servers to
execute a specific task very quickly and support data-intensive projects such as live-streaming and
real-time data processing
Storage clusters
offer massive storage arrays,
sometimes in support of high-performance clusters,
but always in a support role for other servers or clusters such as storage area networking or
hypervisor cluster data stores
Full Backups
- The process backs up everything regardless of whether the archive bit is set or not:
- Clears the archive bit once the backup completes
- This method takes the longest to back up and the time depends on how much must be backed up
- A full backup is quickest to restore as only the most recent full backup is required
- A full backup should be scheduled, automated, and tested although it is common to perform this manually
incremental backups
This method backs up any new file or any file that has changed since
* The last full backup
* The last incremental backup
- Subsequent backups only store changes that were made since the previous backup
- An incremental backup clears the archive bit once the backup completes
- The process of restoring lost data from an incremental backup is longer, but the backup process
is much quicker - In is not recommended to perform incremental backups manually
differential backups
This method backs up any file that has the archive
bit set
* Backs up any new file or any file that has changed since the last full backup
* A differential back up DOES NOT clear the archive bit when the backup completes
* It is slow to back up but quick to restore
* The last full backup and the most recent differential backup are needed for restoration
* It is not recommended to perform differential backups manually
snapshots
Are immediate point-in-time virtual copies of the source data
* Offer easier and faster backups and restores
* Should be replicated to another medium or cloud storage to be considered a backup
* Do not increase time to back up based on amount of data
* Improve Recovery Time Objective (RTO) and Recovery Point Objective (RPO)
* Have fast restores
* Result in less data is lost with an outage
* Can easily be encrypted and decrypted
backup frequency
Backup frequency is often based on the business impact analysis metric known as the Recovery Point
Objective (RPO):
* RPO is the maximum amount of data loss that you
can tolerate in case of a disaster
* The lower the RPO, the more frequently you need to
back up your data
journaling
Journaling is also referred to as journal-based
backup
* Journaling is the simultaneous (real-time) logging of all data-file updates
* This log offers an audit trail and is used to reconstruct the database if the original file is damaged or destroyed
* Journal-based backup is an alternate method of backup that uses a change journal maintained by a hardware or software storage manager
encrypting backup
Encrypting the database and other data backups helps secure the data
Continuity of operations plan (COOP) or business
continuity plan (BCP)
helps to ensure that the entity
remains operational at a pre-determined level when
disaster strikes
- These are plans and documents approved by executive management that:
- Outline the risk to business
- Populate risk register/ledger
- Provide requirements to mitigate incidents
- Identify the procedures needed to recover from a
disaster
business impact analysis (BIA)
Recovery Time Objective (RTO)
Maximum tolerable downtime (MTD)
Recovery Point Objective (RPO)
Mean time to repair (MTTR)
Mean time between failures (MTBF)
Mean time between failures (MTBF):
The number of failures per million hours for a product
Mean time to repair (MTTR):
The average time needed to repair or replace a failed system or module
Recovery Point Objective (RPO):
The maximum targeted period in which an asset or data may be lost from an IT service due to a major
event
Maximum tolerable downtime (MTD):
Absolute maximum amount of time that a resource, service, or function can be unavailable
Recovery Time Objective (RTO):
The target amount of time within which a process must be restored after disruption