Po-Yi Chou
undergraduate in EECS in NCTU
Project maintained by poyichou Hosted on GitHub Pages — Theme by mattgraham
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Notes-disk
Mount a new deivce
if your device file is /dev/hda1
# Create a new filesystem using the ext4 filesystem type:
$ mke2fs -t ext4 /dev/hda1
# Mount
$ mount -t ext4 /dev/hda1 /wherever
Disk Scheduler
# check available disk schedulers (in my case, cfq is in use).
$ cat /sys/block/sda/queue/scheduler
noop deadline [cfq]
# enable specific disk scheduler (for example, cfq)
# SCHEDNAME = Desired I/O scheduler
# DEV = device name (e.g., hda)
$ echo SCHEDNAME > /sys/block/DEV/queue/scheduler
# To make it consistent after reboot
# On Grub 2
# Add "elevator=noop" to the GRUB_CMDLINE_LINUX_DEFAULT line.
$ vim /etc/default/grub
$ update-grub
Move whole os to smaller drive (w/ example, i.e. sdc->sdd)
$ lsblk # not related blocks truncated
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sdc 8:32 1 235.5G 0 disk
├─sdc1 8:33 1 512M 0 part
└─sdc2 8:34 1 235G 0 part
sdd 8:48 1 114.6G 0 disk
└─sdd1 8:49 1 114.6G 0 part
To shrink, shrink filesystem then partition
To enlarge, enlarge partition then filesystem
Check filesystem
$ sudo e2fsck /dev/sdc2
e2fsck 1.46.2 (28-Feb-2021)
/dev/sdc2: clean, 204536/15409152 files, 3147421/61608704 blocks
$ sudo e2fsck -f /dev/sdc2
e2fsck 1.46.2 (28-Feb-2021)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/sdc2: 204536/15409152 files (0.2% non-contiguous), 3147421/61608704 block
resize ext2/ext3/ext4 file system
$ sudo resize2fs /dev/sdc2 114G
resize2fs 1.46.2 (28-Feb-2021)
Resizing the filesystem on /dev/sdc2 to 29884416 (4k) blocks.
The filesystem on /dev/sdc2 is now 29884416 (4k) blocks long.
Shrink partition
$ sudo fdisk /dev/sdc
Welcome to fdisk (util-linux 2.36.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): p
Disk /dev/sdc: 235.52 GiB, 252888219648 bytes, 493922304 sectors
Disk model: USB3.0 CRW -SD
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 080B7B7D-7982-4AE4-A8A9-F1FB34D18F97
Device Start End Sectors Size Type
/dev/sdc1 2048 1050623 1048576 512M EFI System
/dev/sdc2 1050624 493920255 492869632 235G Linux filesystem
Command (m for help): d
Partition number (1,2, default 2): 2
Partition 2 has been deleted.
Command (m for help): n
Partition number (2-128, default 2):
First sector (1050624-493922270, default 1050624):
Last sector, +/-sectors or +/-size{K,M,G,T,P} (1050624-493922270, default 493922270): +119537664K
Created a new partition 2 of type 'Linux filesystem' and of size 114 GiB.
Partition #2 contains a ext4 signature.
Do you want to remove the signature? [Y]es/[N]o: N
Command (m for help): p
Disk /dev/sdc: 235.52 GiB, 252888219648 bytes, 493922304 sectors
Disk model: USB3.0 CRW -SD
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 080B7B7D-7982-4AE4-A8A9-F1FB34D18F97
Device Start End Sectors Size Type
/dev/sdc1 2048 1050623 1048576 512M EFI System
/dev/sdc2 1050624 240125951 239075328 114G Linux filesystem
Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.
Recheck filesystem
$ sudo e2fsck -f /dev/sdc2
e2fsck 1.46.2 (28-Feb-2021)
Pass 1: Checking inodes, blocks, and sizes
Inode 8 extent tree (at level 2) could be narrower. Optimize<y>? yes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/sdc2: 204536/7471104 files (0.8% non-contiguous), 2649209/29884416 blocks
Move whole os from sdc to sdd
$ sudo dd if=/dev/sdc of=/dev/sdd # traditional way
#or
$ sudo su -s /bin/bash -c 'pv -s 122944486912 -S < /dev/sdc > /dev/sdd' # speed up and show progress, 122944486912 equals 240125951 (end of partition) * 512 byte
65.4GiB 0:47:32 [22.2MiB/s] [============> ] 27% ETA 2:03:31
partition sdd if you want to use 100% unallocated space
$ sudo parted /dev/sdd
GNU Parted 3.4
Using /dev/sdd
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) p
Model: SanDisk Ultra USB 3.0 (scsi)
Disk /dev/sdd: 123GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 1049kB 538MB 537MB fat32 EFI System Partition boot, esp
2 538MB 123GB 122GB ext4
(parted) resizepart 2
End? [123GB]? 100%
(parted) q
Information: You may need to update /etc/fstab.
$ sudo e2fsck -f /dev/sdd2
e2fsck 1.46.2 (28-Feb-2021)
Pass 1: Checking inodes, blocks, and sizes
Inode 8 extent tree (at level 2) could be narrower. Optimize<y>? yes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/sdd2: 204544/7471104 files (0.8% non-contiguous), 2653626/29884416 blocks
resize ext4 filesystem to fit
$ sudo resize2fs /dev/sdd2
resize2fs 1.46.2 (28-Feb-2021)
Resizing the filesystem on /dev/sdd2 to 29912827 (4k) blocks.
The filesystem on /dev/sdd2 is now 29912827 (4k) blocks long.
clone disk in windows (msys, slow speed but easy)
# find out device names
$ cat /proc/partitions
major minor #blocks name win-mounts
8 0 1953514584 sda
8 1 16384 sda1
8 2 1023983616 sda2 D:\
8 3 929512448 sda3 F:\
8 16 244198584 sdb
8 17 460800 sdb1
8 18 102400 sdb2
8 19 16384 sdb3
8 20 242815689 sdb4 C:\
8 21 800768 sdb5
8 32 3907018584 sdc
8 33 16384 sdc1
8 34 1023983616 sdc2
8 35 929512448 sdc3
# may need to run msys in administrator mode
# specify bs since default value (512 bytes) might causing slow speed
$ dd if=/dev/sda of=/dev/sdc status=progress bs=128K
clone disk in windows (native, cmd, fast)
download dd for windows in website
find out device names, Partition0 is the entire disk
C:\Dowload\Path\dd-0.5>dd --list
rawwrite dd for windows version 0.5.
Written by John Newbigin <jn@it.swin.edu.au>
This program is covered by the GPL. See copying.txt for details
Win32 Available Volume Information
\\.\Volume{xxx-xxx-xxx-xxx-xxx}\
link to \\?\Device\HarddiskVolume2
fixed media
Mounted on \\.\d:
\\.\Volume{xxx-xxx-xxx-xxx-xxx}\
link to \\?\Device\HarddiskVolume3
fixed media
Mounted on \\.\f:
\\.\Volume{xxx-xxx-xxx-xxx-xxx}\
link to \\?\Device\HarddiskVolume4
fixed media
Not mounted
\\.\Volume{xxx-xxx-xxx-xxx-xxx}\
link to \\?\Device\HarddiskVolume7
fixed media
Mounted on \\.\c:
\\.\Volume{xxx-xxx-xxx-xxx-xxx}\
link to \\?\Device\HarddiskVolume8
fixed media
Not mounted
\\.\Volume{xxx-xxx-xxx-xxx-xxx}\
link to \\?\Device\HarddiskVolume5
fixed media
Not mounted
\\.\Volume{xxx-xxx-xxx-xxx-xxx}\
link to \\?\Device\CdRom0
CD-ROM
Mounted on \\.\e:
NT Block Device Objects
\\?\Device\CdRom0
size is 2147483647 bytes
\\?\Device\Harddisk0\Partition0
link to \\?\Device\Harddisk0\DR0
Fixed hard disk media. Block size = 512
size is 2000398934016 bytes
\\?\Device\Harddisk0\Partition1
link to \\?\Device\HarddiskVolume1
Fixed hard disk media. Block size = 512
size is 16777216 bytes
\\?\Device\Harddisk0\Partition2
link to \\?\Device\HarddiskVolume2
\\?\Device\Harddisk0\Partition3
link to \\?\Device\HarddiskVolume3
\\?\Device\Harddisk1\Partition0
link to \\?\Device\Harddisk1\DR1
Fixed hard disk media. Block size = 512
size is 250059350016 bytes
\\?\Device\Harddisk1\Partition1
link to \\?\Device\HarddiskVolume4
Fixed hard disk media. Block size = 512
size is 471859200 bytes
\\?\Device\Harddisk1\Partition2
link to \\?\Device\HarddiskVolume5
Fixed hard disk media. Block size = 512
size is 104857600 bytes
\\?\Device\Harddisk1\Partition3
link to \\?\Device\HarddiskVolume6
Fixed hard disk media. Block size = 512
size is 16777216 bytes
\\?\Device\Harddisk1\Partition4
link to \\?\Device\HarddiskVolume7
\\?\Device\Harddisk1\Partition5
link to \\?\Device\HarddiskVolume8
Fixed hard disk media. Block size = 512
size is 819986432 bytes
\\?\Device\Harddisk2\Partition0
link to \\?\Device\Harddisk2\DR4
Fixed hard disk media. Block size = 512
size is 4000787030016 bytes
Virtual input devices
/dev/zero (null data)
/dev/random (pseudo-random data)
- (standard input)
Virtual output devices
- (standard output)
–progress make it show copied block
–size makes sure dd not to read past end of an entire device
specify bs since default value (512 bytes) might causing slow speed
C:\Dowload\Path\dd-0.5>dd if=\\?\Device\Harddisk0\Partition0 of=\\?\Device\Harddisk2\Partition0 bs=16M --progress --size