Summarize the usage examples of disk quotas

Disk quota

1 Enable disk quota

First create a new partition /dev/sd5 and create the file system.

[root@local ~]# mkfs.ext4 /dev/sda5

Since xfs cannot succeed without disk quota, ext4 is used here.

Then mount the /dev/sda5 partition to /home

[root@local ~]# mount /dev/sda5 /home

[root@ local ~]# blkid /dev/sda5

/dev/sda5: UUID="8879cf63-99a5-43bb-9bfe-de303afb0799" TYPE="ext4"

Modify/etc /fstab file

[root@local ~]# vim /etc/fstab

UUID=dddd23d1-1012-4bac-9717-56b9b469e0c2 / ext4 defaults 1 1

UUID=316d8677-25b8-49af-b4eb-54daa20b6595 /boot ext4 defaults 1 2

UUID=dacd6ddd-d765-4646-b98c-0579f2732749 swap swap defaults 0 0

UUID=8879cf63-99a5-43bb-9bfe-de303afb0799 /home ext4 defaults,usrquota,grpquota 0 0

usrquota enables the user disk quota function of the disk, and grpquota enables the group disk quota function of the disk.

[root@centos7 ~]# mount –a /home/

Check whether the mount is successful

[root@local ~ ]# mount

sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime,seclabel)

proc on /proc type proc (rw,nosuid,nodev, noexec,relatime)

[……]

/dev/sda5 on /home type ext4 (rw,relatime,seclabel,quota,usrquota,grpquota,data=ordered)

You can see that /dev/sda5 has been mounted correctly

2 Create a quota database

[root@centos7 ~] # quotacheck -cug /home

Since the /etc/fstab file sets usrquota and grpquota, so here must be –cug, u corresponds to usrquota, and g corresponds to grpquota.

Now check the /home directory and there will be two more files, indicating that the disk quota database was created successfully.

[root@local ~]# ll /home/

total 36

-rw-------. 1 root root 7168 Apr 25 11:03 aquota.group

-rw-------. 1 root root 7168 Apr 25 11:03 aquota.user

drwx------. 3 centos centos 4096 Apr 16 10:20 centos

drwx------. 2 root root 16384 Apr 25 10:55 lost+found

3 Enable database

[root@local ~]# quotaon /home/

[root@local ~]

# Come down and check it out, you can see that it was successfully enabled.

[root@local ~]# quotaon -p /home/

group quota on /home (/dev/sda5) is on

user quota on /home ( /dev/sda5) is on

4 Disk quota setting

Set user1 disk quota to 100M, and issue a warning when it reaches 80M

[root@local ~]# edquota user1

Disk quotas for user user1 (uid 1001):

Filesystem blocks soft hard inodes soft hard

/dev/sda5 52 80000 100000 13 0 0

The default unit here is block, and 1 block is 1K. soft is the warning value, hard is the maximum value,

Now let’s confirm whether the configuration is successful

[root@local ~]# quota user1    #查看用户user 的磁盘配额
Disk quotas for user user1 (uid 1001):
Filesystem blocks quota limit grace files quota limit grace
/dev/sda5 52 80000 100000 13 0 0

5 Test

(1) Create the test user user1

[root@local ~]# useradd uesr1

Switch to user1 user

[root@local ~]# su - user1
Last login: Tue Apr 25 11:08:41 CST 2017 on pts/1

(2) Create a file test

First create a 50M file testquota.

[user1@local ~]$ dd if=/dev/zero of=testquota bs=1M count=50
50+0 records in
50+0 records out
52428800 bytes (52 MB) copied, 0.562963 s, 93.1 MB/s

You can see that everything is normal

Let’s create a 35M file testquota2.

[user1@local ~]$ dd if=/dev/zero of=testquota2 bs=1M count=35

sda5: warning, user block quota exceeded.
35+0 records in
35+0 records out
36700160 bytes (37 MB) copied, 0.348267 s, 105 MB/s

Because 50M+35M=85M is greater than 80M

Everyone saw a warning issued this time, but the operation was still successful

Come down and create again A 20M file testquota3.

[user1@local ~]$ dd if=/dev/zero of=testquota3 bs=1M count=20

sda5: write failed, user block limit reached.
dd: error writing 'testquota3': Disk quota exceeded
13+0 records in
12+0 records out
13217792 bytes (13 MB) copied, 0.165029 s, 80.1 MB/s

Creation failed because it has exceeded the maximum value of 100M!

The test is completed and the experiment is over!

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