Cloud Watch Flashcards
CloudWatch Default Host-Level Metrics Consist of
- CPU
- Network
- Disk
- Status Check
True or False: RAM Utilization requires a custom metric?
True
CloudWatch Metrics minimum granularity
1 minute; however, to see 1-minute intervals, you must enable detailed monitoring
CloudWatch Standard intervals
5 minutes
CloudWatch Detailed intervals
1 minute
True or False: CloudWatch Detailed intervals cost more than standard.
True, although there is a free tier for small use cases, there is a higher cost for detailed metrics.
True or False: Default host-level metrics for Disk include available storage.
False. To see storage available on the disk requires a custom metric.
the four different EBS volume types consist of:
General Purpose (SSD) - gp2 Provisioned IOPS (SSD) - io1 Throughput Optimized (HDD) - st1 Cold (HHD) - sc1
EBS General Purpose SSD (gp2) use cases
- Recommended for most workloads
- System boot volumes
- Virtual Desktops
- Low-Latency interactive apps
- Dev/Test environments
EBS Provisioned IOPS SSD (io1) use cases
- Critical applications that require sustained IOPS of more than 10,000 IOPS, or 160 MiB/s throughput per volume
- Large database workloads such as MongoDB, Cassandra, MS SQL
EBS Throughput Optimized HDD (st1) use cases:
- Streaming workloads that require consistent throughput at low cost
- Big Data
- Data warehouses
- Log processing
Can a Throughput Optimized HDD (st1) be used as a boot volume?
No
Cold HDD (sc1) use cases
- Throughput-oriented storage for large volumes of data.
- Infrequently accessed data
- When cost is important
Can Cold HDD (sc1) be used as a boot volume?
No
EBS General Purpose SSD maximum volume size
16,384 GiB
EBS General Purpose SSD maximum IOPS
10,000 IOPS. Use provisioned IOPS for applications requiring more.
Maximum IOPS and throughput - Provisioned IOPS
- 32,000 IOPS
- 500 MB/S throughput
Maximum IOPS and throughput - General Purpose SSD (gp2)
- 10,000 IOPS
- 160MB/s throughput
Maximum IOPS and throughput - Throughput Optimized HDD (st1)
- 500 IOPS
- 500 MB/s Throughput
Maximum IOPS and throughput - Cold HDD (sc1)
- 250 IOPS
- 25 MB/s throughput
EBS baseline IOPS (non-provisioned IOPS)
3 IOPS per GiB. Ex 100GiB EBS volume = 300 IOPS
Minimum EBS volume size (GiB) to achieve maximum 10,000 IOPS for non provisioned IOPS volumes
3,334. Remember AWS baseline IOPS is 3 IOPS per GiB. 3,334 x 3 = 10,002, which provides 10k IOPS.
Should you pre-warm an EBS volume?
No. Pre warming EBS volumes is no longer required to achieve maximum performance.
In order to achieve maximum performace from a snapshot, what needs to be done?
Initialize the volume. Read all the blocks on a restored EBS volume by reading all of the blocks prior to use.
EBS CloudWatch Metrics:
VolumeReadBytes
VolumeWriteBytes
provides information on I/O for a specified period of time. Examples include total transfered bytes, average size of I/O operations.
Units: Bytes
EBS CloudWatch Metrics:
VolumeReadOps
VolumeWriteOps
Total number of I/O operations in a specified period of time.
units: Counts
EBS CloudWatch Metrics:
VolumeTotalReadTime
VolumeTotalWriteTime
The total number of seconds spent by all operations that completed in a specified period of time. If multiple requests are submitted at the same time, the total requests will be greater than the time period measured.
units Seconds
EBS CloudWatch Metrics:
VolumeIdleTime
The total number of seconds in a specified period of time when no read or write operations were submitted.
Units: Seconds
EBS CloudWatch Metrics:
VolumeQueueLength
The number of read and write operation requests waiting to be completed in a specified period of time. If the number is greater than 0, you should adjust your disk to increase IOPS.
EBS CloudWatch Metrics:
VolumeThroughputPercentage
Provisioned IOPS only. The percentage of I/O operations per second delivered or the total IOPS provisioned.
Units: Percent
EBS CloudWatch Metrics:
VolumeConsumedReadWriteOps
Provisioned IOPS only. Total number of read and write operations in a specified period of time.
units: Count
Explain how an I/O operation works
I/O are normalized at 256k. Operations =<256k=1 IOPS. Operations >256k equal 2 or more, in increments of 256k. Ex, a 1024k operation will equal 4 IOPS. That is 1024/256=4.
EBS CloudWatch Metrics:
Name the volume status check statuses
- Ok - Normal
- Warning - Degraded, or severely degraded. Operating below expectations.
- Impaired - Stalled, Not available. Severely impacted, or disabled.
- Insufficient Data - Insufficient Data. Likely a new metric still collecting data.
Can you modify an EBS volume?
Yes, in current generation EC2 instance types.
How can you modify an EBS volume?
Issue the modification command via console or command line.
True or False, when you increase an EBS volume, the OS immediatly has access to the extra storage space?
False: You must go into the OS and extend the volume.
Are Dashboards multi-region?
Yes: Just create a widget and change the desired region.
Do widgets and dashboards auto-save while you create them?
No. Remember to save.
True or false: You can retrieve log data from any terminated EC2 or ELB instance after it’s terminated?
True: CloudWatch logs are by default stored indefinitely.
Can CloudWatch be used for on-premises resources?
Yes.
What are the requirements for using CloudWatch on-prem?
Download and install the SSM and CloudWatch agents.
What is the maximum EBS IOPS burst?
- You can spend IOPS credits to burst IOPS at a lower volume size. Think 3 to 1 IOPS to GiB ratio.
What size is an IO operation standardized?
256k
If an IO operation is greater than 256k, how does AWS handle this?
Take the size of the operation and divide by 256k
If an IO operation is 1024k, how many IO operations is this?
Four operations. 1024 (size of operation) / 256 (size of one IO)
Name this volume status:
Ok
Normal
Name this volume status:
Stalled, Not available. Severely impacted, or disabled.
Impaired
Name this volume status:
Insufficient Data
Insufficient Data. (Likely a new metric still collecting data.)
Name this volume status:
Degraded, or severely degraded. Operating below expectations
Warning