VL 4 Flashcards
AWS - Resource Distribution
Scalability, fault tolerance in availability because of many regions
AWS - Availability Zones
Two zones have no common points of failure => servers in two zones gain infrastructural redundancy
Communication in one zone is free, between zones not
AWS - SLA
Service Level Agreement
Region level: region is unavailable, when all of your running instances or tasks, deployed in two or more AZs, concurrently have no external connectivity
Instance- level: instance is not available, when your Single EC2 instance has no external connectivity
Xen Hypervisor
3 levels of virtualization: bare metal, hosted, os level
Xen: bare metal Hypervisor
Nitro Hypervisor
Services are now part of the hardware
Amazon Machine Image (AMI)
Copy of server with OS and pre installed software
AMIs are stored in S3
AWS Storages
Amazon Elastic block storage: physical disks accessible to the network
Amazon EC2 Instance Storage: physical disks connected to the server on which VM will be placed
Amazon Elastic File System: Network attached system
Amazon simple storage service: place blob of data
RAID
Increase bandwidth, fault tolerance
(Create copies)
Local storages
RAID
FLASH: non-volatile memory
Single and Multi level Cells
Data center storage
Only flash or SSD
Provisioning of storage
Direct attached storage
Storage area network: independent from LAN
Network Attached Storage
SAN pros
Flexible distribution of devices between clients
Easy replacement of faulty servers with new servers booting the same unit
Easier disaster protection
SAN cons
Shared network bandwidth
Shared performance of storage devices
Security concerns due to transfer data through network
Network attached storage (NAS)
File server attached to the network
Frequently using internally a RAID to get redundancy
Storage virtualization
Block virtualization or file virtualization
Usage:
Flexible mapping, thin provisioning, disk expansion and shrinking, non-disruptive data migration, improved utilization
Block virtualization: Implementation
Host based: host runs virtualization software
Storage device based: disk array provides virtualization level
Network based: virtualization device is in the LAN and connected to SAN
File virtualization
Where file is to find
File systems
Clustered NAS
Distributed File System
Amazon Block Storage
Block level storage which can be mounted
Can be formatted as appropriate
Multiple can be combined into a virtual RAID
Snapshots of block storage volume are stored in S3 for backup or replication
Amazon Instance Storage
Disk attached to the physical host
If stop or terminate instance, all data lost
Amazon Elastic File System
Scalable file storage
Can be created and mounted into instances
Files can be shared among instances
File system has to be explicitly created and destroyed
Amazon Simple Storage Services (s3)
Reliable and inexpressible data storage infrastructure
Two level namespace:
buckets
Objects: file in buckets
High durability but low availability
Amazon EC2 Instance
Running VM which is based on an AMI
Elastic IP Adress
Security Platforms
EC2 classic, EC2-VPC (Virtual Private Cloud)
EC2 access
Through a web services API
AWS Cloud Formation
Model infrastructure
