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
What is the main difference between Gp2 and Gp3?
GP3 removes the IO credit bucket from its architecture.
What is the standard performance that Gp3 can offer?
3000 IOPS or 125 MiB/s
Max volume size for GP3 volumes:
1 GB - 16 TB
How much cheaper is GP3 than GP2?
approx 20%.
Max throughput and IOPS that you can achieve with a GP3 volume:
16000 IOPS or 1000 MiB/s
What is GP3 good for?
- Virtual desktops
- Medium-sized instance databases (MSSQL server, Oracle DB)
- low-latency interactive apps
- dev and test environments
- boot volumes
When should you use GP3 by default over GP2?
When you won’t use more than 3000 IOPS or 125 MiB/s
What is the main benefit of the storage type “Provisioned IOPS SSD (io1/io2)”?
IOPS can be adjusted independently of the size of the volume
How many IOPS can I get per io1/io2 volume?
Up to 64000 IOPS per volume (4 x GP2/GP3).
How many IOPS can I get per io2 Block express volume?
Up to 256000 IOPS per volume (Block express).
io1 and io2 throughput:
1000 MB/s
io2 block express throughput:
4000 MB/s
max volume size with io1/io2?
4GB-16TB
max volume size with io2 block express?
4GB-64TB
IOPS per volume size for io1:
50 IOPS/GB (max)
IOPS per volume size for io2:
500 IOPS/GB (max)
IOPS per volume size for io2 block express:
1000 IOPS/GB (max)
Define what Instance Performance is:
performance achieved between an EC2 instance and the EBS volume - performance cap per individual EC2 instance
What influences the Instance Performance?
- Volume type
- Instance type
- Instance size
What are the Instance performance limits when using io1 volumes?
260000 IOPS & 7500 MB/s
What are the Instance performance limits when using io2 volumes?
160000 IOPS & 4750 MB/s
What are the Instance performance limits when using io2 block express volumes?
260000 IOPS & 7500 MB/s
What are io1 and io2 designed for?
- Designed for super high-performance situations that require low latency and consistently low latency.
- I/O intensive NoSQL & relational databases
- High performance with small volumes
Do io1/io2 have a baseline performance and burst credit architecture?
No.
How many types of HDD-based EBS volumes exist?
3: st1, sc1, and legacy.
st1 sizes:
125GB-16TB
sc1 sizes:
125GB-16TB
Do st1 or sc1 have a baseline performance and burst credit architecture?
Yes.
What is the throughput per volume size for st1?
- 40MB/s/TB - base throughput
- 250MB/s/TB - burst throughput
What is the throughput per volume size for sc1?
- 12MB/s/TB - base throughput
- 80MB/s/TB - burst throughput
Max IOPS and throughput for sc1:
Max 500 IOPS (block size is 1MB) –> Max 500 MB/s
Block size for sc1 and st1?
1MB
What is st1 designed for?
- Frequent access
- Throughput intensive
- Sequential workload (reads and writes)
- Examples: big data, data warehouses, log processing.
What is sc1 designed for?
- Less frequently accessed workloads
- When you don’t worry about performance and need to store a lot of data.
- Colder data requiring fewer scans per day
Max IOPS and throughput for sc1:
Max 250 IOPS (block size = 1MB) –> Max 250 MB/s
What is the lowest cost EBS volume?
sc1
