LINUX-16 DISK QUOTA (RHEL-6)

LINUX-16 DISK QUOTA (RHEL-6)

A way to limit the users to eat disk space.

Quota can be implemented on behalf of,

·         Block size:     limit by block size

·         Inode no:       limit by inode/no of files

Limit is also differentiated in,

·         Soft Limit: For warnings, it’s like a barrier means if you jump the                   barrier you will be notified about the jumping incident.

·         Hard Limit: No way, you jumped the barrier and we notify about your  

               daredevil act. Now we can allow you to cross the limits.

Quota is File system based tool. So we need to enable it on FS first to apply on users.

Quota can be implemented on users and groups.

How to check quota is implemented on FS or not…??

[root@localhost /]# quotacheck -vug /home

quotacheck: Mountpoint (or device) /home not found or has no quota enabled.

quotacheck: Cannot find filesystem to check or filesystem not mounted with quota option.

a: Check all quota-enabled file system

v: Verbose mode

u: Check for user disk quota

g: Check for group disk quota

No quota implemented on /home.

I made following modification in /etc/fstab at /home entry.

[root@localhost /]# grep home /etc/fstab

UUID=0e375c48-ff14-4570-9e8d-d0a5851175cb /home ext4    defaults,usrquota,grpquota        1 2

[root@localhost /]# mount -o remount,rw /home

[root@localhost /]# quotacheck -vug /home

quotacheck: Your kernel probably supports journaled quota but you are not using it. Consider switching to journaled quota to avoid running quotacheck after an unclean shutdown.

quotacheck: Scanning /dev/sdb1 [/home] done

quotacheck: Cannot stat old user quota file: No such file or directory

quotacheck: Cannot stat old group quota file: No such file or directory

quotacheck: Cannot stat old user quota file: No such file or directory

quotacheck: Cannot stat old group quota file: No such file or directory

quotacheck: Checked 12 directories and 8 files

quotacheck: Cannot create new quotafile /home/aquota.user.new: Permission denied

quotacheck: Cannot initialize IO on new quotafile: Permission denied

quotacheck: Cannot create new quotafile /home/aquota.group.new: Permission denied

quotacheck: Cannot initialize IO on new quotafile: Permission denied

Well… quota is unable to create quota DB files by itself, let’s help

[root@localhost /]# touch /home/aquota.user

[root@localhost /]# touch /home/aquota.group

[root@localhost /]# chmod 600 /home/aquota.user

[root@localhost /]# chmod 600 /home/aquota.group

[root@localhost /]# ls -ltr /home

total 44

drwx------. 4 raman  raman   4096 Jan 10 22:30 raman

drwx------. 2 root   root   16384 Jan 10 22:45 lost+found

drwx------. 4 anurag anurag  4096 Jan 10 22:48 anurag

-rw-------. 1 root   root       0 Jan 10 22:59 aquota.user

-rw-------. 1 root   root       0 Jan 10 23:00 aquota.group

[root@localhost /]# quotacheck -avug

quotacheck: Cannot guess format from filename on /dev/sdb1. Please specify format on commandline.

quotacheck: Cannot find filesystem to check or filesystem not mounted with quota option.

[root@localhost /]# quotacheck -vug /home

quotacheck: Cannot guess format from filename on /dev/sdb1. Please specify format on commandline.

quotacheck: Cannot find filesystem to check or filesystem not mounted with quota option.

[root@localhost /]# quotacheck -F vfsv0 -avum

quotacheck: Your kernel probably supports journaled quota but you are not using it. Consider switching to journaled quota to avoid running quotacheck after an unclean shutdown.

quotacheck: WARNING -  Quotafile /home/aquota.user was probably truncated. Cannot save quota settings...

[root@localhost home]# quotacheck -cfmvF vfsv0 /home

quotacheck: Your kernel probably supports journaled quota but you are not using it. Consider switching to journaled quota to avoid running quotacheck after an unclean shutdown.

quotacheck: Scanning /dev/sdb1 [/home] done

quotacheck: Cannot stat old user quota file: No such file or directory

quotacheck: Cannot stat old group quota file: No such file or directory

quotacheck: Checked 12 directories and 8 files

quotacheck: Cannot create new quotafile /home/aquota.user.new: Permission denied

quotacheck: Cannot initialize IO on new quotafile: Permission denied

[root@localhost home]# rm aquota.user aquota.group

rm: remove regular empty file `aquota.user'? y

rm: remove regular empty file `aquota.group'? y

Culprit is SELINUX….

[root@localhost home]# setenforce 0

[root@localhost home]# quotacheck -cfmvF vfsv0 /home

quotacheck: Your kernel probably supports journaled quota but you are not using it. Consider switching to journaled quota to avoid running quotacheck after an unclean shutdown.

quotacheck: Scanning /dev/sdb1 [/home] done

quotacheck: Cannot stat old user quota file: No such file or directory

quotacheck: Cannot stat old group quota file: No such file or directory

quotacheck: Checked 12 directories and 8 files

quotacheck: Old file not found.

quotacheck : Command.

c : create the aquota.user file.

f : Forces checking and writing of new quota files on filesystems with

    quotas enabled.

m : This flag forces checking of filesystem in read-write mode if a           remount fails Do this only when you are sure no process will write to     a filesystem while scanning.

v : Display verbose status information as the quota check proceeds.

F : Format Name.

vfsv0 : quota version.

[root@localhost home]# quotacheck -avug

quotacheck: Your kernel probably supports journaled quota but you are not using it. Consider switching to journaled quota to avoid running quotacheck after an unclean shutdown.

quotacheck: Scanning /dev/sdb1 [/home] done

quotacheck: Cannot stat old group quota file: No such file or directory

quotacheck: Cannot stat old group quota file: No such file or directory

quotacheck: Checked 12 directories and 9 files

quotacheck: Old file not found.

[root@localhost /]# mount -o remount,rw /home

[root@localhost /]# quotacheck -avug

quotacheck: Your kernel probably supports journaled quota but you are not using it. Consider switching to journaled quota to avoid running quotacheck after an unclean shutdown.

quotacheck: Scanning /dev/sdb1 [/home] done

quotacheck: Checked 12 directories and 10 files

[root@localhost /]# ls -l /home

total 60

drwx------. 4 anurag anurag  4096 Jan 10 22:48 anurag

-rw-------. 1 root   root    7168 Jan 10 23:14 aquota.group

-rw-------. 1 root   root    7168 Jan 10 23:14 aquota.user

drwx------. 2 root   root   16384 Jan 10 22:45 lost+found

drwx------. 4 raman  raman   4096 Jan 10 22:30 raman

Now the QUOTA DB files are created.

Time to turn the quota ON…………..

[root@localhost /]# quotaon -v /home

/dev/sdb1 [/home]: group quotas turned on

/dev/sdb1 [/home]: user quotas turned on

[root@localhost ~]# mount |grep /home

/dev/sdb1 on /home type ext4 (rw,usrquota,grpquota)

Now time to assign quota to user/group………..

[root@localhost /]# edquota user1

Disk quotas for user user1 (uid 502):

  Filesystem                   blocks       soft       hard     inodes     soft     hard

  /dev/sdb1                        32          0          0          8        0        0

Field description………….

Blocks: 1k blocks

Inodes: Number of entries in directory file

Soft:   Max number of blocks/inodes user may have on partition before warning is         issued and grace persiod countdown begins.

        If set to "0" (zero) then no limit is enforced.

Hard:   Max number of blocks/inodes user may have on partition.

        If set to "0" (zero) then no limit is enforced.

[root@localhost /]# edquota user1

Disk quotas for user user1 (uid 502):

  Filesystem                   blocks       soft       hard     inodes     soft     hard

  /dev/sdb1                    0            20000      25000       0        0        0

Check the status of quota on particular FS…………………………

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

group quota on /home (/dev/sdb1) is on

user quota on /home (/dev/sdb1) is on

How to set quota for particular user………………….

[root@localhost ~]# edquota raman

Disk quotas for user raman (uid 501):

  Filesystem                   blocks       soft       hard     inodes     soft     hard

  /dev/sdb1                        0       10000       15000     0          0        0

How to check the per user quota status on a FS…………………………..

[root@localhost ~]# repquota /home

*** Report for user quotas on device /dev/sdb1

Block grace time: 7days; Inode grace time: 7days

                        Block limits                File limits

User            used    soft    hard  grace    used  soft  hard  grace

----------------------------------------------------------------------

root      --      40       0       0              3     0     0

anurag    --      36       0       0              9     0     0

raman     --      32   10000   15000              8     0     0

user1     --      32   20000   25000              8     0     0

[raman@localhost ~]$ dd if=/dev/zero of=f1 bs=1024 count=9000

9000+0 records in

9000+0 records out

9216000 bytes (9.2 MB) copied, 0.116678 s, 79.0 MB/s

[raman@localhost ~]$ dd if=/dev/zero of=f2 bs=1024 count=3000

sdb1: warning, user block quota exceeded. çSoft Limit Warning

3000+0 records in

3000+0 records out

3072000 bytes (3.1 MB) copied, 0.0555907 s, 55.3 MB/s

[raman@localhost ~]$ ls -lh

total 12M

-rw-rw-r--. 1 raman raman 8.8M Jan 11 22:19 f1

-rw-rw-r--. 1 raman raman 3.0M Jan 11 22:20 f2

[raman@localhost ~]$ dd if=/dev/zero of=f3 bs=1024 count=6000

sdb1: write failed, user block limit reached.

dd: writing `f3': Disk quota exceeded çHard limit warning

2969+0 records in

2968+0 records out

3039232 bytes (3.0 MB) copied, 0.065144 s, 46.7 MB/s

[raman@localhost ~]$ ls -lh

total 15M

-rw-rw-r--. 1 raman raman 8.8M Jan 11 22:19 f1

-rw-rw-r--. 1 raman raman 3.0M Jan 11 22:20 f2

-rw-rw-r--. 1 raman raman 2.9M Jan 11 22:20 f3 çcheck the size

[raman@localhost ~]$

Checking quota report…………………………………………..

[root@localhost ~]# quota -u raman

Disk quotas for user raman (uid 501):

     Filesystem  blocks   quota   limit   grace   files   quota   limit   grace

      /dev/sdb1   15000*  10000   15000   6days      12       0       0

[root@localhost ~]# repquota -a

*** Report for user quotas on device /dev/sdb1

Block grace time: 7days; Inode grace time: 7days

                        Block limits                File limits

User            used    soft    hard  grace    used  soft  hard  grace

----------------------------------------------------------------------

root      --      40       0       0              3     0     0

anurag    --      36       0       0              9     0     0

raman     +-   15000   10000   15000  6days      12     0     0

user1     --      32   20000   25000              8     0     0

Grace Period…………………………………..

[root@localhost ~]# edquota -t

Grace period before enforcing soft limits for users:

Time units may be: days, hours, minutes, or seconds

  Filesystem             Block grace period     Inode grace period

  /dev/sdb1                     7days                  7days

[root@localhost ~]# edquota -t

Grace period before enforcing soft limits for users:

Time units may be: days, hours, minutes, or seconds

  Filesystem             Block grace period     Inode grace period

  /dev/sdb1                     2days                  7days

[root@localhost ~]# quota -u raman

Disk quotas for user raman (uid 501):

     Filesystem  blocks   quota   limit   grace   files   quota   limit   grace

      /dev/sdb1   15000*  10000   15000   6days      12       0       0

[root@localhost ~]# edquota -T raman

Times to enforce softlimit for user raman (uid 501):

Time units may be: days, hours, minutes, or seconds

  Filesystem                         block grace               inode grace

  /dev/sdb1                                 2days                  unset

INTELLIGENT MOVE…………REALLY……??

I wanted to implement the grace period to be effective right now.

[root@localhost ~]# quotacheck -cugm /home

quotacheck: Quota for users is enabled on mountpoint /home so quotacheck might damage the file.

Please turn quotas off or use -f to force checking.

Flag Meaning………….

-c Performs a new scan.

-v Performs a verbose scan.

-u Scans for user quotas.

-g Scans for group quotas.

-m Remounts the scanned filesystem.

Then I used “-f”

[root@localhost ~]# quotacheck -cugmf /home

[root@localhost ~]# quota -u raman

Disk quotas for user raman (uid 501): none  è???????????

[root@localhost ~]# repquota -a

*** Report for user quotas on device /dev/sdb1

Block grace time: 7days; Inode grace time: 7days

                        Block limits                File limits

User            used    soft    hard  grace    used  soft  hard  grace

----------------------------------------------------------------------

root      --      40       0       0              3     0     0

anurag    --      36       0       0              9     0     0

raman     --   15000       0       0             12     0     0

user1     --      32       0       0              8     0     0

ALL GONE……………………..

Read carefully the warning msg given in o/p of “quotacheck -cugm /home”

TURN OFF QUOTA……………

Remove the quota related entries from /etc/fstab.

[root@localhost ~]# quotaoff -auvg

/dev/sdb1 [/home]: group quotas turned off

/dev/sdb1 [/home]: user quotas turned off