Large Values for Bytes

Absolute thresholds for checks (e.g. “bytes used”) are much easier to write and understand if written as kB, MB, MiB or GB instead of long byte-numbers.


--warning=1000000B can be written as --warning=1MB

--critical=2048B can be written as --critical=2kiB

Generic Format

SI-prefix[B] (The B for Bytes is optional if no SI-factor is used. So 100B can be written as 100 as well.)

SI-Prefixes are general purpose multiplicators used in the International System of Units (SI). They are also called factor or multiplicator sometimes.

Available prefixes

Our plugins offer all increments from Kilo to Peta in both decimal and binary format:

# Decimal
KB = 1000
MB = 1000 * KB
GB = 1000 * MB
TB = 1000 * GB
PB = 1000 * TB

# Binary
KiB = 1024
MiB = 1024 * KiB
GiB = 1024 * MiB
TiB = 1024 * GiB
PiB = 1024 * TiB

The library is not case-sensitive. Therfore 1mb or 1Mb are always 1 million bytes and not bits as one may assume.

For more information on the implementation please read the libraries docs at

The values in the check’s output (message) are automatically formated and prefixed with the best-fitting SI-factor.