EFS

Question 1

What is open-after-close consistency?

Answer 1

“NFS standard durability rules:
durable after sychronous write operation
durable after application closes a file”

Question 2

What is a mount target?

Answer 2

“A specifically configured interface on an EFS
pick VPC -> pick subnet/AZ -> pick SG allowing NFS(2049) from private EC2sg
Only one mount target per AZ
If multiple subnets only one can create a mount target
All EC2 instances in the AZ can share the single mount target”

Question 3

EFS and VPC peering rules

Answer 3

“Within a single Region (multi VPC in same region)
can use VPC peering using EC2 type T3 and limited others
inter-region
not permitted”

Question 4

EFS and security group rules

Answer 4

Allow access using NFS port (2049)

Question 5

When can you select the “encrypt at rest” option?

Answer 5

“Only during the EFS creation

if you want to encrypt a non encrypted EFS you need to create a new one and copy all the data over”

Question 6

How do you enable encryption during transit?

Answer 6

“Only during mounting of an EC2 can you enable encryption
Include the Transport Layer Security (TLS) flag in your mount command
sudo mount -t efs -o tls EFSaddress:/ /mnt/efs”

Question 7

What is the Max I/O performance mode?

Answer 7

“Optimizes performance when large amounts of EC2 instances are accessing the file system
Higher levels of aggregate throughput and operatoins per second
slightly higher latencies for file operations”

Question 8

bursting vs provisioned throughput performance mode

Answer 8

“Busting will scale itself according to the current demands

Provisioned will maintain a set throughput”

Question 9

What are common EFS use cases?

Answer 9

"connecting up to thousands of EC2s from multiple AZs into one file system
Big data analytics
media processing workflows
content management
web serving
home directories"