Monitoring Disk Usage
Monitoring Disk Usage
The most commonly used command for monitoring disk space usage is /usr/bin/df, which, by default, displays the number of free blocks and files on all currently mounted volumes. Alternatively, many administrators create an alias for df in their shell initialization script (for example, ~/.cshrc for C shell) like df -k, which displays the amount of free disk space in kilobytes. The basic output for df for a SPARC system looks like this:
# df
Filesystem kbytes used avail capacity Mounted on
/dev/dsk/c0t0d0s0 245911 30754 190566 14% /
/dev/dsk/c0t0d0s4 1015679 430787 523952 46% /usr
/proc 0 0 0 0% /proc
fd 0 0 0 0% /dev/fd
/dev/dsk/c0t0d0s3 492871 226184 217400 51% /var
/dev/md/dsk/d1 4119256 3599121 478943 89% /opt
swap 256000 43480 212520 17% /tmp
/dev/dsk/c0t2d0s3 4119256 3684920 393144 91% /disks/vol1
/dev/md/dsk/d0 17398449 12889927 4334538 75% /disks/vol2
/dev/md/dsk/d3 6162349 5990984 109742 99% /disks/vol3
/dev/dsk/c1t1d0s0 8574909 5868862 1848557 77% /disks/vol4
/dev/dsk/c2t3d0s2 1820189 1551628 177552 90% /disks/vol5
/dev/dsk/c1t2d0s0 4124422 3548988 575434 87% /disks/vol6
/dev/dsk/c2t2d0s3 8737664 8281113 456551 95% /disks/vol7
/dev/md/dsk/d2 8181953 6803556 1296578 84% /disks/vol8
client:/disks/junior_developers
4124560 3469376 613944 85% /disks/junior_developers
For an Intel system, the output is similar, although disk slices have a different naming convention:
# df
Filesystem kbytes used avail capacity Mounted on
/proc 0 0 0 0% /proc
/dev/dsk/c0d0s0 73684 22104 44212 34% /
/dev/dsk/c0d0s6 618904 401877 161326 72% /usr
fd 0 0 0 0% /dev/fd
/dev/dsk/c0d0s1 29905 4388 22527 17% /var
/dev/dsk/c0d0s7 7111598 9 7040474 1% /export/home
swap 222516 272 222244 1% /tmp
/vol/dev/diskette0/unnamed_floppy
1423 131 1292 10% /floppy/unnamed_floppy
df has a number of command-line options that can used to customize the collection and display of information. For example,
# df –a
Filesystem kbytes used avail capacity Mounted on
/dev/dsk/c0t0d0s0 245911 30754 190566 14% /
/dev/dsk/c0t0d0s4 1015679 430787 523952 46% /usr
/proc 0 0 0 0% /proc
fd 0 0 0 0% /dev/fd
/dev/dsk/c0t0d0s3 492871 226185 217399 51% /var
/dev/md/dsk/d1 4119256 3599121 478943 89% /opt
swap 256000 43480 212520 17% /tmp
/dev/dsk/c0t2d0s3 4119256 3684920 393144 91% /disks/vol1
/dev/md/dsk/d0 17398449 12889927 4334538 75% /disks/vol2
/dev/md/dsk/d3 6162349 5990984 109742 99% /disks/vol3
/dev/dsk/c1t1d0s0 8574909 5868862 1848557 77% /disks/vol4
/dev/dsk/c2t3d0s2 1820189 1551628 177552 90% /disks/vol5
/dev/dsk/c1t2d0s0 4124422 3548988 575434 87% /disks/vol6
auto_direct 4124560 3469376 613944 85% /disks/www
auto_direct 0 0 0 0% /disks/ftp
server:vold(pid329)
0 0 0 0% /vol
/dev/dsk/c2t2d0s3 8737664 8281113 456551 95% /disks/vol7
/dev/md/dsk/d2 8181953 6803556 1296578 84% /disks/vol8
client:/disks/junior_developers
4124560 3469376 613944 85% /disks/junior_developers
prints usage data for all file systems, even those that have the “ignore” option set in their entries in /etc/mnttab:
# cat /etc/mnttab /dev/dsk/c0t0d0s0 / ufs rw,suid,dev=800000,largefiles 944543087 /dev/dsk/c0t0d0s4 /usr ufs rw,suid,dev=800004,largefiles 944543087 /proc /proc proc rw,suid,dev=29c0000 944543087 fd /dev/fd fd rw,suid,dev=2a80000 944543087 /dev/dsk/c0t0d0s3 /var ufs rw,suid,dev=800003,largefiles 944543087 /dev/md/dsk/d1 /opt ufs suid,rw,largefiles,dev=1540001 944543105 swap /tmp tmpfs ,dev=1 944543105 /dev/dsk/c0t2d0s3 /disks/vol1 ufs suid,rw,largefiles,dev=800013 944543105 /dev/md/dsk/d0 /disks/vol2 ufs nosuid,rw,largefiles,quota,dev=1540000 944543105 /dev/md/dsk/d3 /disks/vol3 ufs nosuid,rw,largefiles,dev=1540003 944543106 /dev/dsk/c1t1d0s0 /disks/vol4 ufs nosuid,rw,largefiles,dev=800080 944543105 /dev/dsk/c2t3d0s2 /disks/vol5 ufs nosuid,rw,largefiles,dev=80010a 944543106 /dev/dsk/c1t2d0s0 /disks/vol6 ufs suid,rw,largefiles,dev=800088 944543106 auto_direct /disks/www autofs ignore,direct,nosuid,dev=2c00001 944543181 auto_direct /disks/ftp autofs ignore,direct,nosuid,dev=2c00002 944543181 server:vold(pid329) /vol nfs ignore,noquota,dev=2bc0002 944543192 /dev/dsk/c2t2d0s3 /disks/vol7 ufs nosuid,rw,largefiles,dev=800103 944548661 /dev/md/dsk/d2 /disks/vol8 ufs nosuid,rw,largefiles,quota,dev=1540002 944553321 client:/disks/junior_developers /disks/junior_developers nfs nosuid,dev=2bc0040 944604066
To avoid delays in printing resource information on NFS-mounted volumes, it is also possible to just check local file systems with the following command:
# df –l Filesystem kbytes used avail capacity Mounted on /dev/dsk/c0t0d0s0 245911 30754 190566 14% / /dev/dsk/c0t0d0s4 1015679 430787 523952 46% /usr /proc 0 0 0 0% /proc fd 0 0 0 0% /dev/fd /dev/dsk/c0t0d0s3 492871 226184 217400 51% /var /dev/md/dsk/d1 4119256 3599121 478943 89% /opt swap 256000 43488 212512 17% /tmp /dev/dsk/c0t2d0s3 4119256 3684920 393144 91% /disks/vol1 /dev/md/dsk/d0 17398449 12889901 4334564 75% /disks/vol2 /dev/md/dsk/d3 6162349 5990984 109742 99% /disks/vol3 /dev/dsk/c1t1d0s0 8574909 5868862 1848557 77% /disks/vol4 /dev/dsk/c2t3d0s2 1820189 1551628 177552 90% /disks/vol5 /dev/dsk/c1t2d0s0 4124422 3548988 575434 87% /disks/vol6 /dev/dsk/c2t2d0s3 8737664 8281113 456551 95% /disks/vol7 /dev/md/dsk/d2 8181953 6803556 1296578 84% /disks/vol8
A block device can be specified on the command line, and its individual usage measured—for example, a slice on controller 1:
# df /dev/dsk/c1d0d2 Filesystem kbytes used avail capacity Mounted on /dev/dsk/c1t1d0s0 8574909 5868862 1848557 77% /disks/vol4
Users can also check the status of the disks holding their individual user directories and files by using df. For example,
# df /staff/pwatters Filesystem kbytes used avail capacity Mounted on /dev/md/dsk/d0 17398449 12889146 4335319 75% /disks/vol2
will display the disk space usage for the disk on which the home directory exists for user pwatters, while
# df /tmp/mbox.pwatters Filesystem kbytes used avail capacity Mounted on swap 256000 45392 210608 18% /tmp
checks the size of the partition on which the temporary mailbox for the user pwatters was created by the elm mail-reading program.
| Tip |
The size of the partition on which the temporary mailbox resides is a good thing to check if you intend sending a lot of mail messages! |
Another way of obtaining disk space usage information with more directory-by-directory detail is by using the /usr/bin/du command. This command prints the sum of the sizes of every file in the current directory, and performs the same task recursively for any subdirectories. The size is calculated by adding together all of the file sizes in the directory, where the size for each file is rounded up to the nearest 512-byte block. For example, taking a du of the /etc directory looks like this:
# cd /etc # du 14 ./default 7 ./cron.d 6 ./dfs 8 ./dhcp 201 ./fs/hsfs 681 ./fs/nfs 1 ./fs/proc 209 ./fs/ufs 1093 ./fs 26 ./inet 127 ./init.d 339 ./lib 37 ./mail 4 ./net/ticlts 2429 .
Thus, /etc and all its subdirectories contain a total of 2429 blocks of data. Of course, this kind of output is fairly verbose, and probably not much use in its current form. The size in kilobytes can be displayed by using df –k.
