In this section you will learn how to get disks information, file system information, disk I/O stats and file system stats:

For function reference and examples we assume, that we imported systeminformation as follows:

const si = require('systeminformation');

Disk Layout, Block Devices and Disks IO

All functions in this section return a promise or can be called with a callback function (parameter cb in the function reference)

Function	Result object	Linux	BSD	Mac	Win	Sun	Comments
si.diskLayout(cb)	[{...}]	X		X	X		physical disk layout (array)
	[0].device	X		X			e.g. /dev/sda
	[0].type	X		X	X		HD, SSD, NVMe
	[0].name	X		X	X		disk name
	[0].vendor	X			X		vendor/producer
	[0].size	X		X	X		size in bytes
	[0].totalCylinders				X		total cylinders
	[0].totalHeads				X		total heads
	[0].totalTracks				X		total tracks
	[0].totalSectors				X		total sectors
	[0].tracksPerCylinder				X		tracks per cylinder
	[0].sectorsPerTrack				X		sectors per track
	[0].bytesPerSector				X		bytes per sector
	[0].firmwareRevision	X		X	X		firmware revision
	[0].serialNum	X		X	X		serial number
	[0].interfaceType	X			X		SATA, PCIe, ...
	[0].smartStatus	X		X	X		S.M.A.R.T Status (see Known Issues)
si.blockDevices(cb)	[{...}]	X		X	X		returns array of disks, partitions, raids and roms
	[0].name	X		X	X		name
	[0].type	X		X	X		type
	[0].fstype	X		X	X		file system type (e.g. ext4)
	[0].mount	X		X	X		mount point
	[0].size	X		X	X		size in bytes
	[0].physical	X		X	X		physical type (HDD, SSD, CD/DVD)
	[0].uuid	X		X	X		UUID
	[0].label	X		X	X		label
	[0].model	X		X			model
	[0].serial	X			X		serial
	[0].removable	X		X	X		serial
	[0].protocol	X		X			protocol (SATA, PCI-Express, ...)
si.disksIO(cb)	{...}	X		X			current transfer stats
	rIO	X		X			read IOs on all mounted drives
	wIO	X		X			write IOs on all mounted drives
	tIO	X		X			write IOs on all mounted drives
	rIO_sec	X		X			read IO per sec (* see notes)
	wIO_sec	X		X			write IO per sec (* see notes)
	tIO_sec	X		X			total IO per sec (* see notes)
	ms	X		X			interval length (for per second values)

File System and File System Stats

Function	Result object	Linux	BSD	Mac	Win	Sun	Comments
si.fsSize(cb)	[{...}]	X	X	X	X		returns array of mounted file systems
	[0].fs	X	X	X	X		name of file system
	[0].type	X	X	X	X		type of file system
	[0].size	X	X	X	X		sizes in bytes
	[0].used	X	X	X	X		used in bytes
	[0].use	X	X	X	X		used in %
	[0].mount	X	X	X	X		mount point
si.fsOpenFiles(cb)	{...}	X	X	X			count max/allocated file descriptors
	max	X	X	X			count max
	allocated	X	X	X			count allocated
	available	X	X	X			count available
si.fsStats(cb)	{...}	X		X			current transfer stats
	rx	X		X			bytes read since startup
	wx	X		X			bytes written since startup
	tx	X		X			total bytes read + written since startup
	rx_sec	X		X			bytes read / second (* see notes)
	wx_sec	X		X			bytes written / second (* see notes)
	tx_sec	X		X			total bytes reads + written / second
	ms	X		X			interval length (for per second values)

Getting correct stats values

In disksIO() and fsStats() the results / sec. values (rx_sec, IOPS, ...) are calculated correctly beginning with the second call of the function. It is determined by calculating the difference of transferred bytes / IOs divided by the time between two calls of the function.

The first time you are calling one of this functions, you will get -1 for transfer rates. The second time, you should then get statistics based on the time between the two calls ...

So basically, if you e.g. need a values for filesystem stats stats every second, your code should look like this:

const si = require('systeminformation');

setInterval(function() {
    si.fsStats().then(data => {
        console.log(data);
    })
}, 1000)

Beginning with the second call, you get file system transfer values per second.