- Determine whether you need your HCM system to maintain high availability. If so, you need a minimum of 4 instances. For more information, see Single-instance systems versus multi-instance systems.
-
Determine the number of documents per second being produced by the HCP system
you want to monitor. You can easily do this if you already have an HCM system up
and running:
- Go to the Monitor App: https://system-hostname:6162
- Add the HCP system as a source. For information, see the help that's available from the Monitor App.
- Go to the HCI Admin App: https://system-hostname:8000
- Go to Workflows > Monitor App Workflow > Task > Metrics.
-
View the value for the Average DPS field.
Tip: Let the workflow run for a while to get a more accurate measure for the Average DPS field.
Otherwise, you can get an average documents per second value by doing this:- Select a time period.
- Download the HCP Internal Logs for this time period. For more information, see the help that's accessible from the HCP System Management Console.
- In the downloaded logs for each node, count the number lines logged during the selected time period.
- Add the line value for each node and then divide the sum by the number of seconds in the time window you selected.
- Use this table to determine the number of instances needed based on the number of documents per second produced by your HCP system.
Documents per second Instances needed ≤ 3,200
1
3,201 to 7,200
3
7,201-10,500*
4
*This is the maximum documents per second that HCM currently supports. -
Based on your data availability requirements, determine the number of instances
you need.
Data availability requirement Index replicas needed Instances needed Impact on total documents stored No failure tolerance
1
1 None Survive 2 failed replicas
3
3 3x
Survive 3 failed replicas
4 4 4x
An index with multiple copies remains available in the event of an instance outage. For example, if an index has two copies stored on two instances and one of those instances fails, one copy of the index remains available for servicing requests.
-
Use this formula to determine the total number of documents your HCM system
must be able to store:
documents per second from step 2.
x 3600 seconds in an hour
x 24 hours in a day
x number of days you want to store data (default is 30)
x Impact from the data availability table in step 4.
= Total document count
For example, if your HCP system produces 1500 documents per second, you want to store data for 30 days, and you want to maintain two copies of each index containing the stored data, your system must have enough instances to be able to store roughly 8 billion documents:
1500
x 3600
x 24
x 30
x 2
= 7,776,000,000
- Use this table to determine the number of instances needed based on the total number of documents your HCM must store.
Total document count Instances needed 2 billion or less
1
6 billion or less
3
8 billion or less
4
- Take the highest number of instances from steps 2, 3, and 6. That's the number instances you need.