AWS SAA, EBS, EFs, Fsx, Databases, VPC Flashcards
What is the difference between iops and throughput ?
IOPs is the count of reads and writes per second so its a useful metric for low-latency transactional workloads, Throughputs is the actual measurement of read/write bits per second
What are the 4 EBS volume types ? and what are their uses ?
- General Purpose SSD (gp2, gp3) - boot diskes and general applications 3000 - 16000 IOPS
- Provisioned IOPS SSD (io1, io2) - latency-sensitive applications, suitable for OLTP 64000IOPs 5’9s durability
- Throughput Optimized HDD (st1) - Suitable for big data, ETL (cannot be boot volume)
- Cold HDD (sc1) - Less frequently accessed data
What are volumes ?
Volumes are like virtual hard disks
What is the minimum number of volumes needed per EC2 instance ?
1 this is called the root device volume.
What are snapshots ?
A snapshot is a point in time copy of a volume. A snapshot is a like a photograph of the virtual disk/volume. Snapshots exist on S3
Why does the first snapshot take so long ?
Snapshots are incremental so they alway store the difference between the current snapshot and the last snapshot. Since the first snapshot doesn’t have a snapshot to diff between it takes a long time.
What’s the process for moving a EC2 instance to a different region ?
- Power down your EC2 instance
- Make a snapshot of your EBS volume/s
- Copy your snapshot to your new region
- Make a image from that snapshot
- Make a new EC2 instance using that image.
What are the limitations for sharing snapshots?
You can share snapshots within a region but to uses them in other regions you must first copy them to the new region
What is the locale limitiations for EBS volumes and EC2?
EBS volume must be in the same AZ as the EC2 that uses it.
What is the resizing policy for EBS volumes?
EBS volumes can be resized on the fly without having to stop your EC2 instance but you will need to extend the filesystem in the OS manually
What is the policy for changing EBS volume types?
You can change EBS volume types on the fly without stoping or restarting the instance.
Explain what is meant by EBS end to end encryption ?
- Data at rest is encypted
- Data in flight between the EC2 instance an Volume is encypted
- All snapshots taken of the volume are encrypted
- All volumes created from the snapshot are encrypted
How would you make a encrypted EC2 instance from a non encrypted EC2 instance ?
- Create a snapshot of the unencrypted root device volume
- Create a copy of the snapshot and select the encryption options.
- Create a AMI from the encrypted snapshot
- Use that AMI to launch a new encrypted instances.
What is EC2 Hibernation?
EC2 hibernation preserves the in-memory RAM on persistent storage (EBS)
What is the benefit of using EC2 hibernation ?
Hibernating EC2 instances boot much faster because they don’t need to reload the operating system
What are the limitations of EC2 hibernation?
Limit of 60 day hibernation
Instance RAM must be less than 150GB
Only available for C,M,R (3,4,5) instance families
Available for On-demand and Reserved instances
Support OS Windows, Amazon linux 2, and Ubuntu
What is EFS?
Elastic File System is managed network file system that uses NFSv4 (Network File System version 4) where you only pay for the storage you use. Can scale up to petabytes and data is stored across multiple AZ’s in a region.
What are 4 characteristics of EFS?
- EFS works with EC2 instance in multiple Availability Zones
- Highly available and scalable
- Expensive
- Only compatible with Linux based AMI
What are the two types of EFS storage and what are their use cases?
- General Purpose ( webservers, CMS)
- Max I/O (big data, media processing)
What are the storage tiers for EFS?
- Standard
- Infrequently Accessed
What is FSx for windows?
Fsx for windows is a windows file server that allows you to move windows-based applications that require file storage to AWS
What is the difference between FSx for windows and EFS?
FSx for windows is designed for windows and supports active directory, security policies and other windows filesystem features, EFS is designed for unix / linux
What is amazon FSx for Lustre ?
When you need high-speed, high-capacity distributed storage. Mainly used for high performance computing applications, machine learning and financial modeling. Can store directly to S3
What is the other name for Instance store storage?
Ephemeral storage
What are the restart, stop, terminated characteristics of EC2 instances backed by a instance store?
Instance Store EC2 can be rebooted without losing data.
Instance Store EC2 cannot be stopped
When a Instance Store EC2 is terminated all the data is lost
What are the restart, stop, terminated characteristics of EC2 instances backed by a EBS volume?
Can be rebooted without losing data
Can be stopped without losing data
Can be configured to be deleted without deleting the underlying EBS volume
What is the difference between EBS and Ephemeral Storage AMI’s?
Amazon EBS backed AMI is created from EBS snapshot.
Amazon Instance store backed AMI is created from a template stored in S3
What is a AMI?
A blueprint for an EC2 instance
What is AWS Backup?
It’s a way to allow to consolidate your backups across multiple AWS sevices, EC2, EBS, EFS. Amazon FSx for lustre, Amazon FSx for windows file server, RDS and DynamoDB.
What is the benefit of AWS Backup ?
- Central Management
- Automation
- Improved Compliance
- Can be used with organizations to manage backups across multiple accounts
What is RDS?
RDS is amazons relational database service that supports 6 relational database engines and can be setup in minutes with Multi-AZ support and automatic failover capability.
RDS instances are just dedicated EC2 instances that are running your database engine of choice.
1. SQL Server
2. Oracle
3. MySQL
4. PostgreSQL
5. Aurora
What 6 database engines does RDS Support ?
- SQL Server
- Oracle
- MySQL
- PostgreSQL
- Aurora
What is OLTP and OLAP ?
OLTP is online transaction processing and OLAP is online analytics processing.
OLTP is generally the processing of user transactions like payments and orders and is suitable for RDS
OLAP is the gathering of large scale statistics and metrics line net profit and is generally suitable for services like Redshift
What’s a suitable service for OLTP ?
RDS
What’s a suitable service OLAP?
Redshift
How does amazon manage multi-AZ failover for RDS?
Amazon automatically switches the server the domain name is pointing to because Amazon manages the DNS servers for your RDS instances
What can you use to increase read performance for RDS databases?
Read Replicas
What are read replicas?
Read Replicas are read-only copies of your primary database that can help you increase your read performance. Can be in the same AZ, cross-AZ or cross-region
Do read replicas share the same domain name as the primary database ?
No
What is read replica promotion and what are the consequences for actioning it?
Read replica promotion is when you turn a read replica into a primary database. This enables writing to the database but disables replication with the original primary database. A possible use case for doing this is when you are about to perform OLAP using queries on that database.
What are 3 key facts about read replicas ?
- Scale for read performance not for disaster recovery.
- Require automatic backups to be enabled
- Up to 5 read replicas can be configured for DB instances of MySQL, MariaDB, PostgreSQL, SQL Server and Oracle