Data Size Vocabulary

TB (terabytes) is the typical scale for daily log volumes in medium-to-large production systems. GB is more common for small services. PB is hyperscale (cloud providers, major platforms). MB would be unusually small.

KB (kilobytes) is the natural unit for small API responses. A typical REST JSON response is in the hundreds of bytes to low kilobytes range. MB would suggest a large payload; B (bytes) is too granular for conversational context.

GB is the expected scale for bloated container images. A well-optimised image is tens to hundreds of MB; a poorly optimised one can exceed 1 GB. TB would be unusually large even for the most bloated images.

The discrepancy comes from binary (GiB, 2³⁰) vs decimal (GB, 10⁹) interpretation. The OS reports in binary (1 GiB ≈ 1.074 GB), so 500 GB ÷ 1.074 ≈ 466 GiB — the OS may show ~466 GB. The broader principle is "binary vs decimal prefix".

Petabyte (PB) = 10¹⁵ bytes. The IEC binary equivalent is pebibyte (PiB = 2⁵⁰), but "petabyte" is the common term in most business and engineering conversations. "Perabyte" and "protobyte" are not real units.