linuxexpert-practice-labs/labs/linux-plus/1-3-3-filesystems/README.md

Linux+ 1.3.3: Filesystems

An ext4 and an XFS filesystem, running out of inodes with space to spare, a filesystem check, and a quick benchmark.

Before you start

The lab adds two empty 1 GiB spare disks, /dev/loop40 and /dev/loop41 (the chapter's vdb and vdc). They come back at every boot.

Tasks

1. Make an ext4 filesystem with only about 2000 inodes on /dev/loop40, and an XFS filesystem on /dev/loop41. Mount them at /mnt/e and /mnt/x, and compare their space and inodes.
2. Fill /mnt/e with empty files until it runs out of inodes while it still has space. Write the number of files you managed to create to /root/lab-answers/2, then delete them.
3. Unmount /mnt/e and check its filesystem with a forced fsck. Install fio and benchmark /mnt/x (random reads and writes of 4 KiB blocks on a 200 MiB file, for 15 seconds), then remove the test file and unmount /mnt/x.

Hints

• mkfs.ext4 -N, mkfs.xfs; df -hT and df -i.
• for i in $(seq 1 3000); do touch /mnt/e/f$i || break; done; ls /mnt/e | wc -l.
• fsck -f; dumpe2fs -h shows when a filesystem was last checked.
• fio --name=t --filename=/mnt/x/t --size=200M --rw=randrw --bs=4k --direct=1 --runtime=15 --time_based