function resolveSelectedRAM(ram) {
    if(ram?.recommended != null) {
        return `${ram.recommended}M`
    } else {
        // Legacy behavior
        const mem = os.totalmem()
        return mem >= (8*1073741824) ? '4G' : (mem >= (6*1073741824) ? '3G' : '2G')
    }
}
Set the new data directory.

@param {string} dataDirectory The new data directory.