How large a project the hosted service handles

The pass bar

A project size passes when the service meets every condition in this scenario:

1. The server has just compacted the project's change history. Opening a project costs the most in this state.
2. 10 people open the project at the same moment.
3. The same 10 people then edit it for 60 seconds, each making one edit a second.

• Edit confirmation: 95 % of edits are confirmed by the server within 1.5 seconds (p95 ≤ 1.5 s).
• No failures: no out-of-memory stop and no server errors.
• Memory: the server's peak stays at or below 1.5 GiB, inside its 2 GiB limit.

Test setup

• The production server image for x86-64, emulated on a development computer. Emulation makes the server slower than native hardware, so the results are conservative.
• The memory and CPU limits of the production application: 2 GiB of memory without swap, 1.5 CPUs and one server process, with the production settings for merging and versions.
• The database and file storage ran on the same computer, not over a network. A fresh server started for each run.
• Generated LML projects: 40 % requirements in specifications, 20 % functions, 15 % components, 15 % test cases, 5 % risks and the rest inputs and outputs, with three relationships per item.

Results

Load test results after a compaction: 10 opens at once, then 10 editors for 60 seconds

Items	Data sent per open	10 opens took	Edit confirmation p95	Memory peak	Result
50,000	27.2 MB	3.7 s	1.49 s	1,050 MiB	Pass
50,000 (second run)	27.2 MB	3.6 s	1.08 s	981 MiB	Pass
62,500	33.8 MB	5.2 s	1.94 s	1,271 MiB	Fail: p95 over 1.5 s
75,000	40.5 MB	6.0 s	2.90 s	1,322 MiB	Fail: p95 over 1.5 s

• No run had an out-of-memory stop or a server error.
• The typical edit (p50) was confirmed in about 30 ms in every run. The slow edits wait behind the large responses of the simultaneous opens.
• Memory was not the limiting factor up to 75,000 items; edit confirmation time was.

Plan limits

Items per project on each plan

Plan	Items per project
Free / Academic	500 (2,000 in an active class organization)
Individual	5,000
Team	50,000

• The hosted service holds at most 50,000 items per project on every plan. This is the largest size that passed.
• A whole-project save, such as importing a project file, can be at most 64 MB. A project with long texts can reach this size before the item limit.
• What counts as an item: see Pricing.

What was not measured

• Page timings in the browser at 50,000 items, such as opening Home or the Database.
• Sizes between 50,000 and 62,500 items.
• SysML v2 projects, projects with many diagrams, and long rich-text descriptions.
• Several large projects in use at the same moment.

Questions about a model of your size: contact us.