linux FS disk - miservers/miservers GitHub Wiki

Disk & FS

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List all block devices:

# lsblk

List Partitions Under Linux (case android)

# fdisk -l /dev/block/mmcblk0 
# fdisk -l -u=cylinders /sdcard1/qemu/qemu1.img

create a virtual disk of 1MB

dd if=/dev/zero of=disk.img bs=512 count=2000 	

Formate using ext2 FS

# mkfs.ext2 -b 1024 disk.img

Dump disk infos

# dumpe2fs disk.img
# sudo dumpe2fs /dev/sda7  ; for ext2/ext3/ext4

Mount a virtual disk(Android) : use terminalEmulator/root

# mount -o rw,remount /
# mkdir /mnt/tmp
# busybox losetup /dev/block/loop0 /extSdCard/qemu/qemu1.img
# busybox  mount -o loop -t auto /dev/block/loop0  /mnt/tmp
  then you can access the virtual img via /mnt/tmp dir.

Formating an USB or a disk partition

# fdisk -l              ; identify the partition to formate
# umount /dev/sdb1
# mkfs.ntfs /dev/sdb1   ; we always formate a partition not the hole disk.

Online Resizing an FS

# lvresize -L +4G /dev/VolPrddb/db1
# lvresize -L +4G /dev/VolPrddb/db1
# resize2fs -p /dev/VolPrddb/db1 +8G
# resize2fs  /dev/VolPrddb/db1

RAID

RAID 5 : https://www.dataretrieval.com/raid-data-recovery/raid-5-internals-data-storage-performance-and-recovery.html

Create a ISO 9660 image

From a devide or cdrom

dd if=/dev/sda1 of=~/disk1_image.iso

From a directory

mkisofs -o /tmp/cd.iso /tmp/directory/ 

mount an iso file

sudo mount /path/to/cd.iso /mnt/cdrom -o loop

Ext4 FileSystem internals

Create and formate a disk image

dd if=/dev/zero of=disk.img bs=512 count=2000 # 1MB image
pkg install e2fsprogs
mkfs -b 4096 -t ext4 disk.img # 4kB blocks

Dump an Inode

stat employee.json

Clean Disk Space

list of 10 biggest Directories

du -h / | sort -hr | head -n 10

Clear Apt Cache

apt clean