remountsize

Remountsize is a term used to describe the size parameter applied when remounting a filesystem, particularly tmpfs, to alter its in-memory storage limit. It is not a separate command, but a concept found in documentation and man pages describing how to adjust the allocated memory for a mounted filesystem without unmounting it.

In Linux and other Unix-like systems, the mount system supports a remount operation that can change options on a currently mounted filesystem. For tmpfs, the size= option specifies the maximum amount of memory the filesystem may use. Remounting with a new size allows administrators to increase or decrease the in-memory quota while the system is running, avoiding downtime associated with unmounting.

Usage typically involves remounting with the desired size on the target mount point. For example, to increase a tmpfs mount at /tmp, one might use: sudo mount -o remount,size=4G /tmp. Similarly, for a mount at /dev/shm, the command would reflect the appropriate mount point and desired size. The exact syntax can depend on the system and how the filesystem is mounted in fstab, but the core idea is changing the size option without a full remount.

Considerations and limitations include memory management and system stability. The size parameter sets a maximum, not a guarantee of reserved memory. Increasing the size reduces the memory available for other processes; decreasing may fail if the filesystem currently uses more space than the new limit. Changes may persist across reboots if recorded in /etc/fstab; otherwise they are temporary and apply only to the current runtime.

See also: remount, mount, tmpfs, fstab.