framework/requirements/YiiRequirementChecker.php
function compareByteSize($a, $b, $compare = '>=')
    {
        $compareExpression = '(' . $this->getByteSize($a) . $compare . $this->getByteSize($b) . ')';

        return $this->evaluateExpression($compareExpression);
    }
function compareByteSize($a, $b, $compare = '>=')
    {
        $compareExpression = '(' . $this->getByteSize($a) . $compare . $this->getByteSize($b) . ')';

        return $this->evaluateExpression($compareExpression);
    }
Compare byte sizes of values given in the verbose representation,
like '5M', '15K' etc.
@param string $a first value.
@param string $b second value.
@param string $compare comparison operator, by default '>='.
@return bool comparison result.