Inspect and adjust ext2/3/4 superblock settings for reliability and performance. 19.12.2025 | reading time: 3 min On ext2/3/4 filesystems tune2fs lets the administrator inspect and change superblock parameters such as reserved blocks, check intervals, mount counts and the volume label; this hands-on guide shows concrete commands and safety notes to get things done. Quick example: inspect and change Start by listing the superblock information and then change two common settings to concrete values, for example: ```bash tune2fs -l /dev/sdb1 ``` Possible relevant lines from the output: ```text Filesystem volume name: data Filesystem UUID: 123e4567-e89b-12d3-a456-426655440000 Last mounted on: /mnt/data Mount count: 5 Maximum mount count: 20 Last checked: Mon Jan 6 12:34:56 2025 Check interval: 15552000 Reserved block count: 32768 Default mount options: user_xattr acl ``` To lower reserved blocks and set a 6 month check interval run: ```bash tune2fs -m 1 /dev/sdb1 tune2fs -i 6m /dev/sdb1 ``` Expect short confirmations and then re-run `tune2fs -l /dev/sdb1` to verify the new values; unmount the filesystem or mount read-only when working on production devices to avoid data risk. Other useful parameters Beyond `-m` and `-i` there are practical flags to keep in the toolbox: use `-l` to list all superblock fields, `-c` to set maximum mount count and `-C` to set current mount count manually, `-L` to change the volume label and `-U` to set a new UUID, and `-e` to change the behavior on errors; changing some features with `-O` or modifying UUIDs can be risky, so document, unmount and back up before applying those. Tools that complement tune2fs Tune2fs sits among commands that inspect and modify ext filesystems: use `dumpe2fs` for extended metadata dumps, `e2label` for quick label changes, `fsck` or `fsck.ext4` for repairs, `mke2fs` to create filesystems with desired features and `blkid` to discover device UUIDs and types before you change things. Small wrap and next steps Tune2fs is fast and powerful, but its changes live at the superblock level so administrators must verify, back up and prefer unmounted operations before applying them; keep practicing with non-production images and consider formal study to deepen skills, for example pursuing CompTIA Linux+ or LPIC-1 and intensive exam preparation at bitsandbytes.academy. Join Bits & Bytes Academy First class LINUX exam preparation. filesystem utilities storage troubleshooting
