How to use this log retention storage calculator
Enter the daily log volume, the retention days for the hot, warm and cold tiers and the compression saving for each, and the page reports the steady-state storage total, how it spreads across tiers and the rotated file count. Set a tier to 0 days if you do not use it.
How it is calculated
Each tier is daily volume times retention days times one minus the compression saving, and the total is the sum of the three. Rotated file counts use the raw, uncompressed volume: ceil(raw volume / maximum file size), computed separately for one day and for the whole hot tier, each rounded up once at the end. As of October 2026 no recognised retention period exists and the answer depends on regulatory and audit requirements, so days and compression rates stay inputs. GB and TB use 1,024.
Limits and cautions
These are steady-state figures that assume a constant daily volume, so traffic spikes land above them. Growth rate and disk exhaustion belong to a different tool. Index size, replica count and metadata are excluded, and keeping a search index alongside raises real usage substantially.
Frequently asked questions
It is the total once the retention window has turned over, so the volume arriving equals the volume being deleted. At that point new logs land each day while the oldest ones drop off, and the total stops growing. How fast logs accumulate and when a disk fills up are out of scope.
Heavy compression still loses to a much longer window. Compression differs by a factor of a few, while retention days differ by tens, so adjusting the retention period moves the total far more than squeezing the files harder.
The maximum file size and the retention window together pile thousands of files into one directory. Too many files slow down directory listings and backups, so the count helps you decide whether to raise the rotation size or split by date into subdirectories.