AI agents consume all your memory in linux by default

A developer traced repeated freezes on a 64 GB Linux workstation to roughly 22 GB of agent-created files accumulating in a tmpfs-backed /tmp, where contents live in RAM or swap and cannot be discarded like ordinary disk cache. The writeup recommends diagnosing the mount with findmnt, df and du, then either redirecting agents to a disk-backed directory via TMPDIR or masking systemd's tmp.mount so /tmp falls back to the root filesystem. The author notes the behavior is not unique to AI workloads, since compilers such as GCC also create temporary intermediate files, but parallel coding agents made the memory trade-off visible.

My 64 GB Linux workstation kept freezing while coding agents worked on a couple of projects. All 4 GB of swap filled up. Applications were killed. Half the memory looked like cache. Then I found 22 GB of agent-created files in a tmpfs-backed /tmp . tmpfs stores file contents in RAM or swap . Unlike clean disk-backed cache, those contents cannot simply be discarded. Some memory monitors include tmpfs in cache-related accounting, making the memory pressure easy to misread.<sup 1</sup Memory-backed temporary storage can offer fast I/O, fewer storage writes, and cleanup on reboot. But swapping can undermine those benefits.<sup 2</sup The distinction is workload size. Systemd recommends /tmp for small, bounded files and /var/tmp for larger data.<sup 3</sup This is not uniquely an AI problem: GCC also creates temporary intermediate files.<sup 4</sup Parallel agent work simply made the trade-off visible on my machine. Run these in a Linux terminal: Filesystem containing /tmp findmnt -T /tmp -o TARGET,SOURCE,FSTYPE Capacity and usage of that filesystem df -hT /tmp Directory sizes, largest last; stay on one filesystem sudo du -x -h --max-depth=1 /tmp | sort -h RAM and swap usage free -h Look for tmpfs under FSTYPE . Keep -T : plain findmnt /tmp can return nothing when /tmp is not a separate mount.<sup 5</sup df measures the containing filesystem; du measures the directory tree.<sup 6</sup <sup 7</sup In free , focus on available .<sup 8</sup Large tmpfs usage alongside low available memory deserves investigation—not automatic blame for every crash. Create a private directory and check its filesystem and free space: mkdir -p "$HOME/.local/tmp" chmod 700 "$HOME/.local/tmp" findmnt -T "$HOME/.local/tmp" -o TARGET,SOURCE,FSTYPE df -hT "$HOME/.local/tmp" mkdir -p creates missing directories; chmod 700 restricts ordinary access to the owner.<sup 9</sup <sup 10</sup Confirm the directory is disk-backed before proceeding. export TMPDIR="$HOME/.local/tmp" Launch your agent from that same terminal. Programs honoring TMPDIR can use the new location. Hard-coded /tmp paths and existing workspaces need separate changes.<sup 3</sup Verify the path and filesystem inside the agent’s actual execution environment , especially with containers or sandboxes.<sup 5</sup Clean up completed scratch data yourself; this directory does not inherit /tmp ’s cleanup policy.<sup 3</sup /tmp disk-backed system-wide For systemd-based distributions, inspect first: Mount unit and any overrides systemctl cat tmp.mount --no-pager Explicit /tmp configuration; no output means no matching entry findmnt --fstab --mountpoint /tmp Root filesystem, mount options, and free space findmnt -T / -o TARGET,SOURCE,FSTYPE,OPTIONS df -hT / tmp.mount is one name, with a dot.<sup 11</sup Use the following only when /tmp is tmpfs, its unit is distribution-provided with no local customizations, /etc/fstab has no /tmp entry, and / is writable, disk-backed, and has adequate space. Otherwise, use Option 1 rather than forcing this shortcut.<sup 5</sup <sup 11</sup sudo systemctl mask tmp.mount This prevents future activation without unmounting the current /tmp .<sup 11</sup Save your work, copy anything needed out of /tmp , then reboot when ready. Existing tmpfs files disappear; they do not migrate to disk. <sup 1</sup After reboot, verify: findmnt -T /tmp -o TARGET,SOURCE,FSTYPE /tmp should now belong to the disk-backed root filesystem. To reverse the mask, run sudo systemctl unmask tmp.mount , then reboot.<sup 11</sup This trades memory-backed storage for root-disk usage and can remove mount-specific restrictions such as nosuid,nodev . Disk space, cleanup, and security policy still matter.<sup 12</sup <sup 3</sup Native macOS and Windows normally use disk-backed temporary directories , so large temporary trees primarily consume disk space.<sup 13</sup <sup 14</sup They can still exhaust memory; disk-backed does not mean cache-free.<sup 15</sup For Linux containers or virtual machines, check inside that environment.<sup 5</sup This is not a reason to disable tmpfs everywhere. It is a reason to put multi-gigabyte workspaces on storage chosen deliberately. “Temporary” describes how long data is needed—not where it belongs. Linux kernel: Tmpfs https://www.kernel.org/doc/html/latest/filesystems/tmpfs.html . ↩ Ubuntu: Data Driven Analysis — /tmp on tmpfs https://ubuntu.com/blog/data-driven-analysis-tmp-on-tmpfs . ↩ systemd: Using /tmp/ and /var/tmp/ Safely https://systemd.io/TEMPORARY DIRECTORIES/ . ↩ GCC: Environment Variables https://gcc.gnu.org/onlinedocs/gcc/Environment-Variables.html . ↩ findmnt 8 https://man7.org/linux/man-pages/man8/findmnt.8.html . ↩ df 1 https://man7.org/linux/man-pages/man1/df.1.html . ↩ du 1 https://man7.org/linux/man-pages/man1/du.1.html . ↩ free 1 https://man7.org/linux/man-pages/man1/free.1.html . ↩ mkdir 1 https://man7.org/linux/man-pages/man1/mkdir.1.html . ↩ chmod 1 https://man7.org/linux/man-pages/man1/chmod.1.html . ↩ systemctl 1 https://man7.org/linux/man-pages/man1/systemctl.1.html . ↩ systemd: upstream tmp.mount https://raw.githubusercontent.com/systemd/systemd/main/units/tmp.mount . ↩ Apple: File System Basics https://developer.apple.com/library/archive/documentation/FileManagement/Conceptual/FileSystemProgrammingGuide/FileSystemOverview/FileSystemOverview.html . ↩ Microsoft: GetTempPath2 https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-gettemppath2a . ↩ Microsoft: File Caching https://learn.microsoft.com/en-us/windows/win32/fileio/file-caching . ↩