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Supported memory and CPU combinations

Supported memory and CPU combinations

IBM Cloud® Code Engine applications, jobs, and functions consume CPU and memory. These amounts can vary, depending on if your workload is compute-intensive, memory-intensive, or balanced.

The use of ephemeral storage is now bounded by memory. The ephemeral storage in Code Engine cannot exceed the default value of 0.4 GB (400 MB) or the configured value for memory. If you need more than the default for ephemeral storage, you must increase your memory according to the valid combinations of vCPU and memory.

Consider the following examples of setting valid values for ephemeral storage:

  • If memory is set to 0.25 GB, you can set ephemeral storage up to the default value of 0.4 GB.
  • If ephemeral storage is set to 0.4 GB and memory is set to 2 GB, and you want to reduce the memory to 0.25 GB, this operation is valid because the ephemeral storage is set to its default value.
  • If ephemeral storage is set to 0.5 GB and memory is set to 2 GB, and you want to reduce the memory to 0.25 GB, this operation is not valid because the ephemeral storage is now greater than the memory and its default of 0.4 GB. The ephemeral storage cannot exceed the default value of 0.4 GB or the configured value for memory.
  • If ephemeral storage is set to 1 GB and memory is set to 4 GB, and you want to increase the ephemeral storage to 4 GB, this operation is valid because the ephemeral storage is less than or equal to the memory.
  • If ephemeral storage is set to 1 GB and memory is set to 4 GB, and you want to reduce the memory to 2 GB, this operation is valid because the ephemeral storage is less than or equal to the memory.

For more information about memory or CPU limitations, see Limits and quotas for Code Engine.

Supported combinations for apps and jobs

See the following table for valid combinations of vCPU and memory for apps and jobs.

The default combination for apps and jobs is 1 vCPU and 4 GB memory.

Table 1. Valid vCPU and memory combinations
CPU-intensive Balanced Memory-intensive
0.125 vCPU
0.25 GB
0.125 vCPU
0.5 GB
0.125 vCPU
1 GB
0.25 vCPU
0.5 GB
0.25 vCPU
1 GB
0.25 vCPU
2 GB
0.5 vCPU
1 GB
0.5 vCPU
2 GB
0.5 vCPU
4 GB
1 vCPU
2 GB
(default for apps and jobs)
1 vCPU
4 GB
1 vCPU
8 GB
2 vCPU
4 GB
2 vCPU
8 GB
2 vCPU
16 GB
4 vCPU
8 GB
4 vCPU
16 GB
4 vCPU
32 GB
6 vCPU
12 GB
6 vCPU
24 GB
6 vCPU
48 GB
8 vCPU
16 GB
8 vCPU
32 GB
10 vCPU
20 GB
10 vCPU
40 GB
12 vCPU
24 GB
12 vCPU
48 GB

Your existing apps and jobs might be using other memory and CPU combinations, and those will remain unaffected. However, these other combinations are not valid and only the valid combinations are supported. Therefore, any new apps or jobs as well as any changes to existing apps or jobs must comply with the list of valid choices.

Supported combinations for functions

See the following list for valid combinations of CPU and memory for functions.

  • 0.25 vCPU and 1 GB memory
  • 0.5 vCPU and 2 GB memory
  • 1 vCPU and 4 GB memory (Default)

Units of measurement

Decimal units such as kilobyte (KB), megabyte (MB), and gigabyte (GB) are commonly used to express the size of data. Binary units of measurement include kibibyte (KiB), mebibyte (MiB), and gibibyte (GiB). The following table compares the names, symbols, and values of decimal and binary units.

Table 2. Comparison of binary and decimal units and values
Binary name Binary value (base 2) Decimal name Decimal value (base 10)
kibibyte (KiB) 2^10 kilobyte (KB) 10^3
mebibyte (MiB) 2^20 megabyte (MB) 10^6
gibibyte (GiB) 2^30 gigabyte (GB) 10^9
tebibyte (TiB) 2^40 terabyte (TB) 10^12