Skip to main content

Disk Quotas: Limit Storage

Disk quotas limit how much space users can use. Prevents one user from filling the disk.

Here's the thing: Quotas are useful for multi-user systems. You might not need them. But when you do, they're essential.

What Quotas Do​

Quotas limit:

  • Disk space per user/group
  • Number of files (inodes)
  • Prevent disk full issues

My take: Quotas are like storage allowances. Each user gets a limit.

Enabling Quotas​

Edit /etc/fstab​

# Add usrquota,grpquota to options
UUID=xxx /home ext4 defaults,usrquota,grpquota 0 2

My take: Enable quotas in fstab. Then remount.

Remount and Enable​

sudo mount -o remount /home
sudo quotacheck -ugam
sudo quotaon -ug /home

My take: Remount. Check quotas. Enable them.

Setting Quotas​

edquota: Edit Quotas​

sudo edquota username

Quota format:

Filesystem  blocks  soft  hard  inodes  soft  hard
/dev/sda1   1000    5000  10000  100    500   1000

Fields:

  • blocks = Current usage
  • soft = Soft limit (warning)
  • hard = Hard limit (enforced)

My take: Soft limit warns. Hard limit enforces. Set both.

Checking Quotas​

quota username                     # User quota
quota -g groupname                # Group quota
repquota /home                    # All quotas

My take: Check quotas to see usage. Monitor them.

When to Use Quotas​

Use quotas when:

  • Multiple users share disk
  • Need to prevent disk full
  • Want to control usage
  • Compliance requirements

Don't use quotas when:

  • Single user system
  • Don't need limits
  • Simple setup

My take: Quotas are for multi-user systems. Use them when needed.

Common Mistakes (I've Made These)​

  1. Not enabling in fstab: Quotas must be enabled in fstab. Don't forget.

  2. Not running quotacheck: Run quotacheck after enabling. Creates quota files.

  3. Wrong limits: Set reasonable limits. Too low frustrates users. Too high defeats purpose.

  4. Not monitoring: Quotas need monitoring. Check usage regularly.

  5. Forgetting to enable: Enable quotas after setup. quotaon enables them.

Real-World Examples​

Set User Quota​

# Enable quotas
sudo edquota username
# Set limits in editor

# Check quota
quota username

Set Group Quota​

sudo edquota -g developers

What's Next?​

Now that you understand quotas, you can limit storage. Or learn about Backup Strategies to protect data.

Personal note: Quotas seemed unnecessary at first. Then I had a user fill the disk. Now I use quotas. They prevent problems. Use them on multi-user systems.