REPORTED QUESTIONS WITH
ANSWERS (GRADED A)
RAID (Redundant Array of Independent Disks) - Answer-- RAID is a way of grouping
individual physical drives together to form one bigger drive called a RAID set
- Enabled system uses 2 or more hard disks to improve the performance or provide
some level of fault tolerance for a machine typically a NAS or server
- RAID can make many smaller disks appear as one large disk to a deserve
- A way of storing the same data in different places on multiple hard disks to protect
data in the case of a drive failure
RAID 0 - Answer-- Gives you higher transfer rates on read and write, while giving you
the capacity of the sum of the drives included on the array
- No redundancy - if a drive fails, you lose the entire array
- Used to boost a server's performance
RAID 1 - Answer-- Gives you higher read rates, but slower write rates, and is only the
capacity of one disc, since the other is a mirror
- Has redundancy, so if one drive fails, the other is a clone and you keep on going
- A fault-tolerance configuration known as "disk mirroring" - data is copied seamlessly
and simultaneously, from one disk to another, creating a replica, or mirror (Causes a
slight drag on performance)
RAID 5 - Answer-- By far the most common RAID configuration for business servers
and enterprise NAS devices
- This RAID level provides better performance than mirroring as well as fault tolerance
- With RAID 5, data and parity (which is additional data used for recovery) are stripped
across 3 or more disks. If a disk gets an error or starts to fail, data is recreated from this
distributed data and parity block - seamlessly and automatically
RAID 6 - Answer-- Used frequently in enterprises
, - Identical to RAID 5, except it's an even more robust solution because it uses one more
parity block than RAID 5
- You can have 2 disks die and still have a system be operational
RAID 10 - Answer-- Combination of RAID 1 and 0 - often denoted as RAID 1+0
- Combines the mirroring of RAID 1 with the striping of RAID 0
- Gives the best performance, but is also costly, requiring twice as many disks as other
RAID levels, for a minimum of four
- This is the RAID level ideal for highly utilized database servers or any server that's
performing many write operations
CIDR (Classless Inter-Domain Routing) - Answer-- A set of Internet Protocol standards
that is used to create unique identifiers for networks and individual devices
- The IP addresses allow particular information packets to be sent to specific computers
Hypervisor - Answer-- Hypervisors provide several benefits to the enterprise data center
- They provide the ability of a physical host system to run multiple guest VM's, which
can vastly improve the utilization of the underlying hardware
- Where physical (non virtualized) servers might only host one operating system and
application, a hypervisor virtualizes the server, allowing the system to host multiple VM
instances, each running an independent operating system and application, on the same
physical system, using far more of the system's available compute resources
CDN (Content Delivery Network) - Answer-- Improves the performance, security and
reliability of a website
- A CDN has Points of Presence (PoPs) or data centers that are situation around the
world. Within each PoP are thousands of servers. Both the PoPs and servers help
accelerate the speed at which content is delivered to the end user
Docker - Answer-- Docker is a popular open source project based on Linux containers.
It is written in go and developed by Dotcloud (A PaaS company)
- Docker is basically a container engine which uses the Linux Kernal features like
namespaces and control groups to create containers on top of an operating system and
automates application deployment on the container