This is an original planning guide. It is not a vendor manual, an official standard, or legal advice. Example addresses use documentation ranges. Review every command before you paste it.
What this hour is for
The calculator multiplies the rate and the retention you enter. Index overhead and replicas are extra. Measure the rate. Do not order a product from the page.
The browser tool does not connect to a SIEM.
192.0.2.10/24, gateway 192.0.2.1, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. example.com is a documentation name. A sample password is replaced. It is not a password you keep.
The change you can finish
Apply nothing while you are writing the note. When the lab window opens, it is one change on the system named in the ticket. Read the draft, then the system, then decide.
Rollback is the file, the record, or the snapshot you saved first. You do not invent a rollback after the only copy is gone.
- Write the events per second you measured.
- Write the days.
- Read the estimate.
- Add a sentence that overhead is extra.
- Stop.
Mistakes that outlive the statement
How to Size a SIEM goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- A guessed rate treated as a bill.
- A purchase made from the page.
- A SIEM installed during the reading.
Decisions to write down
One decision for How to Size a SIEM: The rate was measured. The number is an estimate. And nothing was bought.
Checks before you call it done
Confirm this before you call the change done: The rate is written. The days are written. The estimate was read. Nothing was bought. And the logs are yours. If one of those fails, stop.
# Size estimate. Not a purchase order.
# 192.0.2.10/24, gateway 192.0.2.1, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. example.com is a documentation name. A sample password is replaced. It is not a password you keep.Before you leave the system
How to Size a SIEM ends when the system in the note is the system in the ticket. If it is not, stop.
The draft stays a draft until a person has read the names in it. A generator does not log in, does not scan, and does not send mail.
192.0.2.10/24, gateway 192.0.2.1, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. example.com is a documentation name. They belong in the note. They are not values you publish because a draft included them.
prompt-for-this is a reminder that a secret is missing. It is not a password, a key, or a token you save. A sample password is replaced. It is not a password you keep.
One change is the window. If two things move and the result is wrong, you will not know which one did it.
If the same step fails twice, stop for the day. Restore the copy you took first.
A second person reads the scope aloud. If they cannot find it in the ticket, the note is not done.
This page is a planning guide. It is not legal advice, not an audit opinion, not a vendor manual, and not the text of a standard. You do not disable a security control to make a check pass. You do not use the page against a system you do not administer.
Tools for this guide
These tools run in the browser on this site. They do not log into your machines.
Related pillar guides
More in this cluster
The pillar for this page, and the next published pages filed with it.