Reserved Cycles Limit

Developers
1

I have some questions regarding the Reserved Cycles Limit in a canister.

If I create a canister with e.g 1 T of cycles then the cycles balance will be 992_307_591_078 Cycles and the Reserved Cycles Limit displays 5_000_000_000_000 Cycles.

dfx canister create --with-cycles 1T my_counter2
dfx canister status my_counter2

In my cycles wallet there is only a reduction of 1T.

dfx wallet balance

My questions are:

  1. Where are the Reserved Cycles Limit cycles come from ?
  2. What is the purpose of that value ?
  3. What does Reserved: 0 Cycles mean in the dfx canister status output ?

I can’t find a clear explanation for myself in the documents. Thanks for making that a bit clearer.

2

Hi @rbole,

The reserved cycles limit is just a limit, not actual cycles. This limit controls how large reserved cycles can get.

More details:

3

Hi, with reserved cycles do you mean the cycles balance of the canister ?

4

A canister has two cycles balances:

  • the main cycles balance (this is what appears as simply “cycles” in the status)
  • the reserved cycles balance. It is a separate balance that hold cycles reserved for future resource payments such as storage. In most cases it will be 0. In some cases when the subnet usage is reaching its capacity, allocating resources will require reserving cycles as explained in the links I shared.
5

Thank you very much.

1 Like