L4 - IAAS 2/2 Flashcards
What is block virtualization?
Meta data determine mapping of
virtual disk and block number (local in the client systems) to physical disc, block number.
- IO redirection based on the
meta-data
Usage of storage virtualization
Flexible mapping
Thin provisioning
Disk expansion and shrinking
Non-disruptive data migration
Improved utilization
Is file or block virtualization used more often?
block virtualization is used more often and also performs beter
How is block storage accessed?
Though SAN
3 Methods of block virtualization implementation
- host based
- storage device based
- network based
What is host-based block virtualisation?
- host runs virtualization software
- it maps logical units to physical units
What is file virtualization?
- used for NAS
- you have folders and files
What are the pros of file virtualization?
- highly scalable
- accessible to multiple runtimes
Which file systems are used in file virtualization?
- NTFS, FAT32, UFS
What is clustered NAS?
- clustered NAS combines NAS from the same vendor
What is DFS?
Distributed file systems
- allows files located on multiple NAS to appear as if on a single NAS
- can combine NASs from different vendors
Amazon Block Storage
- block-level storage that can be mounted
- multiple block storage volumes can be combined into a virtual RAID
- snapshots of block storage volume are stored in S3 for backup or replication
What is mounting?
When a block-level storage is “mounted,” it means that it is being connected to the operating system so that it can be accessed and used. The process of mounting makes a block-level storage available to the host operating system, allowing it to read and write data to the storage.
What is Amazon Instance Storage?
- disks attached to the physical host
- if you stop or terminate an instance, the data on the instance store volumes is lost
What is Amazon Elastic File System?
- scalable file storage
- can be mounted to instances
- files can be shared among instances
- file system has to be explicitly created and destroyed
Amazon S3
Amazon Simple Storage Service (S3)
- up to 5 TB
- two-level namespaces
- access in Amazon EC2 or from the web
Pros and cons of Amazon S3
Pros: reliable and inexpensive storage infrastructure, durable
Cons: slow compared to local disks or EBS, low availability
-> used for backup
What are the two-level namespaces for Amazon S3?
In summary, Amazon S3 uses a bucket as the top-level namespace and an object key as the second-level namespace to organize and access data stored in the service.
IBM’s differentiation of file and block storage based on use case
Block:
- boot volume
- lowest latency
File:
- mix of structured or unstructured data
- share data with many users at once
What is an instance?
running VM that is based on an Amazon Machine Image (AMI)
Possible storage options for EC2 Instances?
- boot device volume
- instance store volumes: local discs of the server
- EFS
- EBS
Which types of storage are lost when the EC2 instance is terminated?
- boot device volume and instance store volume
- for persistency use EFS and EBS
Do you get an elastic IP for EC2 Instances?
Yes, an Elastic IP address is static; it does not change over time. An Elastic IP address is for use in a specific Region only, and cannot be moved to a different Region.
What are EBS-backed instances?
are those where the root file system is in the elastic block storage.
Is data retained after instance is terminated in EBS-backed instances?
Yes. In Amazon instance store-backed this is not the case.
Is there a stopped state for EBS-backed instances?
Yes. Here the root volume is persistent. For Amazon instance store-backed there is no stopped state.
what is hibernate?
When the memory content should be saved
What is EC2 - VPC?
Virtual private cloud (before there was also EC2 classic)
- your resources are launched into your VPC
- VPC resembles your network in your own data center
How can EC2 be accessed?
- primarily through web service API
- interactive tools on top of the API (Amazon Web Services Console, Amazon Command Line tools)
- third-party infrastructure tools (flexera)
- access to server by private or public key pair
AWS cloud formation
model your infrastructure
- infrastructure as a code
- specify all resources in a textual way as a json template
- allows standardizing components across your institution
- automatic deployment of resources
- use code editor and versioning tools
3 types of pricing
- on-demand pricing
- reserved instances pricing (you reserve an instance for an entire month and save money compared to on-demand pricing)
- pricing spot-market (VM price depends on AWS capacity left)
