How Many Disks Read/write Requests Have Been Made on My Linux System
In this commodity I will share different commands and methods to bank check disk space in Linux. Most of these commands and methods should be bachelor on most Linux distros. You can besides utilise these commands to create a script to monitor deejay size usage and create alarms or send mails (this would need a mail server).
ane. Check partition size using df command
df is one of the nigh used command to bank check space of available partitions on the Linux setup. You tin can use df wih -Th to print the partition type and the partition size in man readable format. This command will show you the full bachelor, used and free space per sectionalisation.
You lot tin also use other arguments such equally -i to impress the available, used and gratis inode count per partition:
Y'all can check the homo page of df command for other supported arguments to check disk space in different formats.
2. Bank check disk space using fdisk utility
fdisk is another very handy utility for system administrators. fdisk is a user interactive program mostly used for creation and manipulation of division tables such as creating, deleting, modifying partitions. Just nosotros can likewise use this utility to list the available disks connected to the Linux arrangement along with the respective deejay size.
Here is a snippet of output from command "fdisk -l"
As you can see from the output, I have a deejay /dev/sda with a size of 15GB. The output also shows more details about this disks wherein it contains 2 partitions /dev/sda1 and /dev/sda2.
The output of fdisk -fifty can be quiet long so if yous just wish to check the disk space then you can use this command:
~]# fdisk -l | awk '$i=="Disk" && $two ~ /^\/dev\/.*/ {print $2 $3 $4}' /dev/sda:15GiB, /dev/sdb:8GiB, /dev/mapper/rhel-root:14GiB, /dev/mapper/rhel-swap:512MiB, Hither I take combined fdisk with awk to only print required sections. So I accept 2 disks with 15GB and 8GB each, while I accept two LVM partitions which are most likely function of these disks with a size of 14GB and 512MB.
3. Check disk infinite using parted utility
parted is another alternative to fdisk and is likewise used for manipulating disk partitions. It is useful for creating space for new operating systems, reorganising deejay usage, and copying data to new hard disks.
Like to fdisk, we can utilise parted -l to list all the bachelor disks forth with their respective size:
If yous compare the output of parted with fdisk, hither we only become the available disk and their size and the LVM details are missing which is a good thing every bit we only wanted to check the disk space.
We tin also use awk with parted to further only print required output:
~]# parted -l | awk '$ane=="Disk" && $2 ~ /^\/dev\/.*/ {print $2 $3 $4}' /dev/sda:16.1GB /dev/sdb:8590MB 4. Check file size using du command
du is some other wonderful utility to check the size of files recursively in Linux. It can also summarize disk usage of the set of files, recursively for directories. du is a very versatile tool and supports multiple arguments which you can use based on your requirement. Some of the most used arguments are:
-a, --all write counts for all files, not just directories -c, --full produce a g total -d, --max-depth=North impress the full for a directory (or file, with --all) only if it is N or fewer levels beneath the com‐ mand line statement; --max-depth=0 is the same as --summarize -h, --man-readable print sizes in human readable format (east.g., 1K 234M 2G) -s, --summarize display just a full for each argument -t, --threshold=SIZE exclude entries smaller than SIZE if positive, or entries greater than SIZE if negative
Hither are some instance demonstrating unlike scenarios to check file organisation size using du command:
EG-1: Check size of all the files under a partition recursively
I have a separate partition for /boot:
~]# df -h /boot/ Filesystem Size Used Avail Use% Mounted on /dev/sda1 488M 123M 330M 28% /boot
And so let's check the size of all the files nether /boot using du -h /boot/*
EG-2: Print total summary of size of files in a partition or directory
We can apply du -c to print a full or summary of all the file size nether provided directory or partition.
~]# du -sch /etc/iscsi/* iv.0K /etc/iscsi/initiatorname.iscsi 16K /etc/iscsi/iscsid.conf 20K total So the total file size under /etc/iscsi directory is 20K. You can also use this command nether root i.e. du -sch /* to get a summary and total size of all the files under /
EG-3: Sort the output based on file size
Past default the du control will print the size of the file based on the beginning available directory or sub-directory. And so the output is non sorted and it tin exist a tedious task to get through the long listing. We tin combine du with sort command do sort the output based on the file size.
Hither we have used du with sort -hour where -h is used to compare human readable numbers such as 2K, 1G, 4M etc while -r is used to reverse the order of search.
EG-four: Impress file size larger than specified size
Past default du will print the size of every file institute under a sectionalisation or directory. We can add a threshold to print files higher than a certain size.
For example hither nosotros are printing the files with size college than 1MB nether /var/log
~]# du -ach -t 1M /var/log/* | sort -hr 19M total 8.9M /var/log/anaconda 4.2M /var/log/anaconda/lvm.log 3.2M /var/log/anaconda/journal.log 1.9M /var/log/dnf.librepo.log one.6M /var/log/inspect/inspect.log 1.6M /var/log/inspect For more than list of supported options cheque the human being folio of du command.
5. Check disk size using lsblk command
lsblk lists data about all bachelor or the specified block devices. The lsblk command reads the sysfs filesystem and udev db to gather information. If the udev db is not available or lsblk is compiled without udev support than it tries to read LABELs, UUIDs and filesystem types from the block device.
We can utilise lsblk with -o LIST or --output Listing to go desired columns based on the value of List. Utilise lsblk --help to go a list of all supported columns.
Nosotros volition use name, fstype, size, mountpoint LIST for our example. Although using only size and name was enough simply to requite more detailed output I am using additional list options.
six. Print deejay size using blockdev
We can use blockdev command to impress a report for the specified device. Information technology is possible to give multiple devices. If none is given, all devices which appear in /proc/partitions are shown. Notation that the sectionalization StartSec is in 512-byte sectors.
You lot can also use following commands:
# returns size in bytes. # blockdev --getsize64 /dev/sda # returns size in 512-byte sectors. # blockdev --getsz /dev/sda
7. Check disk size and details using lshw command
lshw is a small tool to excerpt detailed information on the hardware configuration of the car. It can report exact retentivity configuration, firmware version, mainboard configuration, CPU version and speed, cache configuration, bus speed, etc. on DMI-capable x86 or IA-64 systems and on some PowerPC machines.
By default lshw volition give you a huge output, we tin limit that by only printing the information for a specified form such as "disk". To get the list of fastened disks and their details such as size we will use lshw -c disk.
Here is an output snippet from my Linux node:
We tin farther improve the output using lshw with grep:
~]# lshw -c disk | grep -E "logical proper noun|size:" logical name: /dev/sda size: 15GiB (16GB) logical name: /dev/sdb size: 8GiB (8589MB)
eight. Checking disk size from the system logs
We tin besides use arrangement logs such every bit boot logs using dmesg or journalctl -b and attempt to search for respective deejay to get more information. The catch is that y'all should know the disk proper name dissimilar other methods which we discussed where we were able to check size of all the bachelor disks without prior knowledge of disk name.
For instance, here I am searching for all instance of sda disk in kicking logs using dmesg:
Similarly we can search for any other disk, such equally sdb:
~]# dmesg | grep sdb [ 3.230296] sd 3:0:0:0: [sdb] 16777216 512-byte logical blocks: (8.59 GB/eight.00 GiB) [ 3.230304] sd 3:0:0:0: [sdb] Write Protect is off [ 3.230306] sd 3:0:0:0: [sdb] Mode Sense: 00 3a 00 00 [ iii.230316] sd three:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [ iii.238804] sdb: sdb1 [ 3.239698] sd three:0:0:0: [sdb] Attached SCSI disk
You may also try grepping blocks in dmesg output which can list the available disk with their size:
~]# dmesg | grep blocks [ three.228462] sd 2:0:0:0: [sda] 31457280 512-byte logical blocks: (16.1 GB/15.0 GiB) [ iii.230296] sd three:0:0:0: [sdb] 16777216 512-byte logical blocks: (8.59 GB/eight.00 GiB)
9. Cheque deejay size using lsscsi control
lsscsi uses information in sysfs (Linux kernel series ii.half-dozen and after) to listing SCSI devices (or hosts) currently attached to the system. Many non-SCSI storage devices (simply not all) used the SCSI subsystem in Linux. In lsscsi version 0.30 support was added to list NVMe devices.
We tin can apply lsscsi --size to list all the connected storage devices forth with their size as shown below:
~]# lsscsi --size [0:0:0:0] cd/dvd VBOX CD-ROM 1.0 /dev/sr0 - [1:0:0:0] cd/dvd VBOX CD-ROM i.0 /dev/sr1 - [two:0:0:0] disk ATA VBOX HARDDISK ane.0 /dev/sda sixteen.1GB [three:0:0:0] deejay ATA VBOX HARDDISK 1.0 /dev/sdb 8.58GB
10. Print disk size using sfdisk
sfdisk is again an alternative to fdisk and parted utility. One of the major difference betwixt fdisk and sfdisk is that sfdisk reads and writes partition tables, but is not interactive like fdisk or cfdisk (information technology reads input from a file or stdin). It's more often than not used for partitioning drives from scripts or for partition table fill-in and recovery.
But it can also be used to check the disk size using sfdisk -l, sample output:
Summary
In this article we explored different commands and methods which tin can exist used to check deejay size (used/available/full) in Linux. You tin can hands utilize most of these commands and methods into a script to regularly monitor the bachelor disk space and heighten alert when threshold is reached. There are some more commands such equally udisks, hwinfo which can be used to collect similar information only they are distro dependent and may not be available with all the Linux distributions hence I have skipped them.
Source: https://www.golinuxcloud.com/linux-check-disk-space/
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