SLACKWARE SSD PERFORMANCE TUNING

OVERVIEW

This document describes a minimal and explicit approach to improving SSD
and NVMe performance on Slackware.

The focus is on reducing write amplification, maintaining consistent
performance over time, and extending drive lifespan using native Linux
and Slackware mechanisms. No third-party tools or background services
are required.


DESIGN GOALS

- rely on Slackware-native tools
- avoid unnecessary daemons
- keep configuration auditable and simple
- prioritize long-term SSD health over micro-optimizations
- ensure predictable system behavior


ASSUMPTIONS

- Slackware is running on the system
- the system uses SSD or NVMe storage
- filesystems in use support TRIM (e.g. ext4, xfs)
- the user has root access


ABOUT TRIM AND FSTRIM

TRIM allows the operating system to inform an SSD which blocks are no
longer in use by the filesystem.

This enables the SSD controller to:

- erase unused blocks efficiently
- reduce write amplification
- maintain consistent write performance
- extend the lifespan of the drive

The fstrim utility performs TRIM operations on mounted filesystems.
Unlike continuous discard mount options, fstrim runs explicitly and in
a controlled manner.


WHY PERIODIC FSTRIM

Running fstrim periodically is preferred over continuous discard
because:

- it avoids performance penalties during normal I/O
- it reduces unnecessary write operations
- it provides predictable execution timing
- it is easier to audit and control

For most systems, running fstrim weekly or at boot is sufficient.


CREATING AN RC.FSTRIM SCRIPT

Slackware does not include a default periodic fstrim mechanism.
This behavior can be added using a simple rc script.

Create the script:

    vim /etc/rc.d/rc.fstrim

Add the following content:

    #!/bin/sh
    #
    # rc.fstrim: Perform filesystem TRIM to maintain SSD/NVMe performance.
    #
    if [ -x /sbin/fstrim ]; then
        echo "Running fstrim on all mounted filesystems..."
        /sbin/fstrim -av
    fi

Make the script executable:

    chmod +x /etc/rc.d/rc.fstrim


ENABLING FSTRIM AT BOOT

To run fstrim automatically at boot, invoke rc.fstrim from rc.local.

Edit rc.local:

    vim /etc/rc.d/rc.local

Add the following lines before `exit 0`:

    # Run TRIM on SSD/NVMe at boot
    if [ -x /etc/rc.d/rc.fstrim ]; then
        /etc/rc.d/rc.fstrim
    fi

This ensures TRIM is performed regularly without introducing a
long-running service.


VERIFICATION

To verify that fstrim runs correctly, execute the script manually:

    /etc/rc.d/rc.fstrim

The output should list mounted filesystems and the number of bytes
trimmed.

If no output is shown, confirm that:

- the filesystem supports TRIM
- the device is an SSD or NVMe drive
- fstrim is available at /sbin/fstrim


NOTES ON FILESYSTEM MOUNT OPTIONS

This document intentionally avoids recommending the `discard` mount
option.

Continuous discard can increase write amplification and introduce
latency during normal filesystem operations. Periodic fstrim provides
better control and more predictable performance.


CONCLUSION

Maintaining SSD performance on Slackware does not require complex tools
or aggressive tuning.

By using periodic fstrim through a simple rc script, SSD and NVMe drives
remain performant and healthy while preserving Slackware’s philosophy
of simplicity, transparency, and administrator control.


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Last Modified: 2026-01-03 05:29:48 UTC