Meaning of the number in AWS instance type name
AWS EC2 uses instance type names like C1, M2, T1, T2, etc. C means CPU and M means memory, but what does the numbers 1, 2 and the letter T mean?
Answer
From official reInvent video:
There is no official explanation as why a letter is chosen for a certain type. To remember, try:
- T for Turbo (Burstable)
- M for Most Scenarios (General Purpose)
- C for Compute
- R for Random-Access Memory
- X for Extra-Large Memory (~4TB DRAM)
- H for HDD (16TB Local)
- D for Dense Storage (48TB Local)
- I for I/O (NVMe Local)
- HS for High Storage
- G for GPU
- P for GPU too (yes, could be confusing)
- F for FPGA
- A for ARM
- Z for High Frequency (sorry ran out of alphabets)
- MAC for mac mini
Also for additional capabilities:
- a for AMD CPUs
- b for Block Storage Optimized
- e for Extra Capacity (Storage or RAM)
- n for Networking Optimized
- d for Directly-Attached Instance Storage (NVMe)
- g for Graviton2 (AWS) processors
- z for High Frequency (again)
Note: In my experience, T could also stand for "Trouble". It's CPU throttling mechanism may trigger a lot of mysterious problems in various applications including the Attunity suite powering AWS's own DMS.
Steer away from it unless you are really good at calculation CPU credits, and you are 100% confident that your application could handle the sudden throttling of computing power.
No, actually, just don't use it.