What Is /var/tmp

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Last updated: April 11, 2026

Quick Answer: /var/tmp is a system temporary directory in Unix and Linux operating systems where applications store temporary files designed to persist across system reboots. Unlike /tmp which is often cleared at boot, files in /var/tmp typically remain for 30+ days, making it essential for large installers, package managers, and database operations.

Key Facts

/var/tmp has been part of Unix/Linux systems since early Unix implementations as part of the Filesystem Hierarchy Standard (FHS)
Files in /var/tmp survive system reboots and are retained for 30+ days by default, unlike /tmp which may be cleared daily
The directory is world-writable with sticky bit permissions (typically 1777) allowing broad access while preventing users from deleting others' files
Most Linux distributions allocate /var/tmp on the /var partition separate from root, giving administrators independent disk space control
Applications including rpm/dpkg package managers, software installers, and database tools routinely use /var/tmp for working files and large data staging

Overview

/var/tmp is a system directory found on Unix and Linux operating systems that serves as a designated location for temporary files created by applications and system processes. Unlike the commonly used /tmp directory, files stored in /var/tmp are designed to persist across system reboots and are subject to longer retention periods.

The directory is part of the Filesystem Hierarchy Standard (FHS), which defines the structure and organization of directories in Unix-like systems. Located under the /var partition, /var/tmp provides a stable intermediate storage solution for applications that need to maintain temporary data across system restarts or extended operation periods. This distinction makes it crucial for large installation processes, database operations, and other applications that cannot afford to lose temporary working files during a system reboot.

How It Works

/var/tmp operates as a standard Unix filesystem directory with specific characteristics and permissions that distinguish it from other temporary storage locations:

Persistent Storage: Files written to /var/tmp remain on the system after a reboot, making it suitable for data that must survive system restarts or long-running operations spanning multiple sessions.
World-Writable Access: The directory is configured as world-writable, allowing any user and application to create files within it, though the sticky bit permission prevents users from deleting others' files without proper privileges.
Extended Retention Policy: While system administrators can configure cleanup schedules, /var/tmp files typically persist for 30 days or longer before automatic deletion, compared to /tmp files which may be cleared daily or at boot time.
Disk Space Allocation: /var/tmp often resides on the /var partition, which may have its own size allocation separate from the root filesystem, allowing administrators to control disk usage independently.
Security Permissions: The directory maintains standard Unix permissions (typically 1777) with the sticky bit enabled, ensuring security while maintaining broad accessibility for legitimate system and user processes.

Key Comparisons

Feature	/var/tmp	/tmp	/dev/shm
Persistence	Survives reboots	Often cleared at boot	Cleared on reboot
Retention Period	30+ days (configurable)	1-7 days typically	No persistent cleanup
Storage Location	Disk-based (/var partition)	Disk or RAM-based	RAM-based (in-memory)
Common Use Cases	Installers, package managers, databases	Short-lived application files	High-speed temporary data
Performance	Standard disk speed	Variable (depends on mount)	Very fast (memory access)

Why It Matters

Application Reliability: Large software installers, package managers like rpm and dpkg, and database backup tools depend on /var/tmp to safely store working files that may be gigabytes in size, ensuring operations complete successfully even if interrupted.
System Administration: System administrators use /var/tmp for maintenance tasks, data migrations, and system recovery operations requiring intermediate storage across multiple boot cycles.
Performance Balance: While slower than /dev/shm (RAM-based), /var/tmp balances performance and capacity, allowing applications to store larger temporary datasets without overwhelming system memory.
Security and Isolation: The sticky bit permission prevents malicious users from deleting or modifying others' temporary files, maintaining system security while preserving broader accessibility for legitimate processes.

Understanding the distinction between /var/tmp and other temporary directories helps developers and administrators choose the appropriate location for temporary files based on persistence requirements, retention expectations, and performance needs. Proper utilization of /var/tmp ensures that critical temporary operations can complete reliably across system restarts and extended operational periods.