quotacheck Command Linux: Check Filesystem Quotas Explained with Examples

In Linux system administration, maintaining and monitoring disk usage is critical. Without proper checks, uncontrolled disk consumption can lead to performance degradation and even system downtime. The quotacheck command plays a vital role in such scenarios by scanning filesystems for disk usage and updating the quota records. If you are a system administrator managing multi-user environments or shared hosting servers, understanding quotacheck is essential.

What is the quotacheck Command in Linux?

The quotacheck command is used in Linux to scan filesystems for disk usage, check consistency of quota files, and create or update the quota databases. These databases are then used by quota tools like edquota and repquota to enforce user and group disk usage restrictions. Essentially, it ensures that disk quota information matches the actual file usage on disk.

Basic Syntax

quotacheck [options] filesystem

Common filesystems: These are usually mentioned in /etc/fstab, such as /home, /, or partitions like /dev/sda1.

Key Options of quotacheck

• -a: Check all filesystems listed in /etc/fstab with quota enabled.
• -u: Check user quotas (default option).
• -g: Check group quotas.
• -c: Create new quota files.
• -v: Verbose mode, shows detailed information during checks.
• -f: Force check even if filesystem is marked as checked.

Practical Examples of quotacheck Command

1. Check All User Quotas on All Filesystems

sudo quotacheck -avug

Explanation:

• -a → all filesystems
• -v → verbose
• -u → user quotas
• -g → group quotas

Sample Output:

Checking quotas for filesystem /home [/dev/sda3]: done
Checking group quotas for /home [/dev/sda3]: done

2. Check a Specific Filesystem

sudo quotacheck -v /dev/sda3

This will scan /dev/sda3 and update its quota database. Ideal for single partition checks.

3. Create New Quota Files

sudo quotacheck -cug /home

This will create fresh quota files (aquota.user and aquota.group) inside the /home partition if they don’t already exist.

4. Force Check on a Mounted Filesystem

sudo quotacheck -fug /home

If the system warns that quota files are already synced, the -f option forces a re-scan.

Interactive Example: Checking and Viewing Quotas

Typically, after running quotacheck, admins verify quotas using repquota:

sudo repquota -a

Sample Output:

*** Report for user quotas on /dev/sda3 (/home) ***
Block grace time: 7days; Inode grace time: 7days
                          Block limits                File limits
User        used   soft   hard    grace    used   soft   hard  grace
---------------------------------------------------------------------- 
alice     510000  500000  600000             50      0      0
bob       120000  150000  200000              8      0      0

When Should You Use quotacheck?

Running quotacheck is essential in these situations:

• After enabling quotas on a new filesystem.
• After system crashes to sync quota records with real usage.
• When usage reports don’t match actual disk consumption.
• For scheduled maintenance (added to cron jobs).

Best Practices

• Always run quotacheck as root or with sudo.
• Avoid running on live, busy filesystems unless required, as it can cause performance lags.
• Use -a to scan all filesystems at once in automated scripts.
• Combine with monitoring tools for proactive disk quota management.

Conclusion

The quotacheck command is a powerful tool for Linux system administrators to maintain disk quota integrity. By scanning filesystems and syncing quota records, it ensures that users and groups adhere to assigned limits, protecting systems from overuse of resources. Whether you are managing shared hosting servers, corporate environments, or cloud-based Linux systems, mastering quotacheck will make your administration tasks more efficient and secure.