Disk - jasper-zanjani/dotfiles GitHub Wiki

Disk blkid cryptsetup dd df dm-crypt dumpe2fs e2fsck e2label eject fdformat fdisk fsck fstrim gdisk hdiutil hdparm ioping iostat [iscsiadm][iscsiadm] lsblk mdadm mke2fs mkfs mkntfs mkswap mount mt parted partprobe partx resize2fs resize4fs sfdisk swapoff swapon tune2fs umount vifs xfs_info xfs_metadump

Logical volume management lvcreate lvdisplay lvextend lvremove lvs lvscan pvcreate pvdisplay pvremove pvs pvscan vgcreate vgdisplay vgextend vgreduce vgremove vgs vgscan

Index node (inode) is a data structure that stores all the information about a file except its name and data Most modern Linux distributions use the ext4 filesystem, which descends from ext3 and ext2, and ultimately ext. Other filesystems in use include btrfs, xfs, and zfs Source: ^ref

Extended File System was first implemented in 1992 by Remy Card to address limitations in the MINIX filesystem, which was used to develop the first Linux kernel. It could address up to 2GB of storage and handle 255-character filenames and had only one timestap per file.

ext2 was developed by Remy Card only a year after ext's release as a commercial-grade filesystem, influenced by BSD's Berkeley Fast File System. It was prone to corruption if the system crashed or lost power while data was being written and performance losses due to fragmentation. Nevertheless, it was quickly and widely adopted, and still used as a format for USB drives.

ext3 was adopted by mainline Linux in 2001 and uses journaling, whereby disk writes are stored as transactions in a special allocation, which allows a rebooted system to roll back incomplete transactions. 3 journaling modes: journal, ordered, and writeback

ext4 was added to mainline Linux in 2008, developed by Theodore Ts'o, and improves upon ext3 but is still reliant on old technology.

• true next-generation filesystem with a problematic license
• ZFS on Linux (ZOL) is considered the ugly stepchild of the ZFS community despite the fact that the Linux implementation has the most features and the most community support
• ZFS is too tightly bound to the operation of the kernel to operate in true userspace, and that is why each implementation is different for operating systems
  • ZFS is too tightly bound to the operation of the kernel to operate in true userspace, and that is why each implementation is different for operating systems
• ZFS is too tightly bound to the operation of the kernel to operate in true userspace, and that is why each implementation is different for operating systems
• LU: 284

B-Tree Filesystem "butter fs" was adopted by SUSE Enterprise Linux, but support was dropped by Red Hat in 2017.

Incorporate full-disk encryption on /dev/sdb1, asking for passphrase twice

cryptsetup --verify-passphrase luksFormat /dev/sdb1

Assign virtual name "storage1" to encrypted disk /dev/sdb1

cryptsetup luksOpen /dev/sdb1 storage1

Implement a simple CPU benchmark by writing 1 GB of zeroes and piping it to md5sum

dd if=/dev/zero bs=1M count=1024 | md5sum

    b c         h       l     o       s t u   w      
    B C         H       L             S     V W      

  a b c d     g   i     l m n o p q   s t u v w x    
            F G   I           O                      

Discover iSCSI targets

iscsiadm discovery

Create a 20 gigabyte logical volume named "Marketing" from volume group {vg1}

lvcreate -L 20G vg1 -n Marketing

Create logical volume named lv1 of size 500G from volume group vg1

lvcreate -L 500G vg1 -n lv1

Resize existent logical volume {Marketing} in volume group {vg1} to have an additional 10 gigabytes of space

lvresize -L +10G /dev/vg1/Marketing

Create an ext4 filesystem on {partition}

mkfs -t ext4 partition

Specify {filesystemtype} to be created

mkfs -T filesystemtype

partx is a utility that provides information on drive partitions to the Linux kernel. [12] Display partition table of a drive

partx --show /dev/sda

Show details of only one partition of a drive

partx --show /dev/sda1

Specify a range of partitions on a drive

partx -o START, END --nr 10 /dev/sda

Add all partitions on a disk to the system

partx -a /dev/sda

Display length in sectors and human-readable size of a partition

partx -o SECTORS,SIZE /dev/sda1 /dev/sda

Remove the last partition

partx -d --nr -1:-1 /dev/sda

Disable headers

partx -o START -g --nr 5 /dev/sda

Script-based partition table editor, similar to fdisk and gdisk, which can be run interactively. It does not interface with GPT format, neither is it designed for large partitions. [^ref][11]

List partitions on all devices

Display size of {partition} or {device} This command produces the size of {partition} (i.e. /dev/sda1) or even {device} (/dev/sda) in blocks

sfdisk -s partition
sfdisk -s device

Apply consistency checks to {partition} or {device}

sfdisk -V partition
sfdisk --verify device

Create a partition

sfdisk device

Save sectors changed This command will allow recovery using the following command

sfdisk /dev/hdd -O hdd-partition-sectors.save

Recovery Man page indicates this flag is no longer supported, and recommends use of dd instead.

sfdisk /dev/hdd -I hdd-partition-sectors.save

Instruct system to begin using {partition} as a swap file

swapon partition

Adjust various ... Run fsck on {/dev/sdb1} on every boot

tune2fs -c 1 /dev/sdb1

Run fsck on {/dev/sda1} at intervals of 60 mounts or 6 months

tune2fs -c 60 -i 6m /dev/sda1

Enable journaling on ext2 partition {/dev/sdc1}

tune2fs -j /dev/sdc1

Assign label "Sales" to logical volume {/dev/vg1/Sales}

tune2fs -L Sales /dev/vg1/Sales