Elastic Block Storage (EBS) Flashcards
Can you allocate EBS volumes from AZ A to an AZ B?
No, EBS volumes can be attached to instances in the same AZ.
Can EBS volumes use to boot the OS of an instance? Is it used often?
Yes, it is used often to boot the OS of an instance.
Volumes are isolate to … (Region, AZ)?
To one AZ.
Describe availability and resilience of the data stored in EBS volumes:
The data is highly available and resilient for the AZ.
All of the data is replicated within that AZ. The entire AZ must have a major fault to go down.
What physical storage types are available in EBS?
SSD and HDD
How is EBS billed?
GB/month and in some cases additional charges for performance or other features.
How are normally EBS volumes presented to ec2 instances or other services?
Via network storage.
Can EC2 instances be attached to multiple instances and services at the same time?
Normally they are used for 1:1 ec2 instances but they can be attached to multiple instances (called multi attach).
Is there any disadvantage of using EBS volumes with multiple ec2 instances or services?
Yes, you need to administrate the storage and avoid collisions while reading/writing data.
EBS volumes can be attached and reattached to…
EC2 instances in the same AZ.
How can you migrate an EBS volume to another AZ?
You can use EBS snapshots.
Explain how EBS snapshots work
EBS snapshots are a backup of a volume taken into S3
What are the advantages of using EBS snapshots?
That the volume data is replicated to multiple AZs in S3 (regional resilience) and can be then used in different AZs to create EBS volumes.
Snapshots can be copied across regions to provide global resilience.
How can you provide global resilience in EBS?
Taking snapshots and copying them to other regions.
For what is normally gp2 or gp3 used?
For general purpose usage.
What is the min/max volume size for gp2/gp3?
Min 1GB
Max 16 TB
Explain how gp2 volume works:
GP2 volumes can provide a max of 3000 IOPS (bursts) or 250 MiB/s.
GP2 has a performance bucket with credits that are refilled based on a called “baseline performance”.
When there is no credit left in the bucket, you cant perform IO operations.
Explain what “Baseline performance” is in GP2 volumes
The baseline performance of a volume is = 100 IO credits per second + 3 IO credits per second per GB of volume size.
How big is the starting GP2 IO credit bucket?
5.4 Million IOPS and they are available immediately.
Explain what depleting and replenishing mean in GP2:
- Depleting is when you consume more credit than you can refill.
- Replenishing is when you consume less than your baseline performance, so your credits are increasing.
What is the maximum throughput that you can achieve by using GP2 volumes?
250 MiB/s
How much is 1 IO credit in KBs?
16 KB
How much data can you transmit in 1 IOPS?
16 KB per second.
What is GP2 good for?
- Boot volumes
- Low latency interactive applications
- DEV and TEST environments