NoBIGTech Wiki Técnico - docu:csheet:sysadm:disks

clone_partition_table

Anonymous (anonymous@undisclosed.example.com) — 2020-07-10T09:44:15+00:00

Export and clone partition table from 1 disk to another For example, assuming that our disk is /dev/sda , to save the partition table we can give the command: sfdisk -d /dev/sda > partitions.txt while to restore it, assuming that the destination disk is /dev/sdb and we want to clone the partition table, we can use the command

get_disk_nice_info

Anonymous (anonymous@undisclosed.example.com) — 2020-05-16T16:43:58+00:00

Get interesting information about a disk/partition using tune2fs For sysadmins, tune2fs -l offers great information about filesystem, like last mount time or last write time 😉👌 tune2fs -l /dev/sdX Source:

get_hw_info

Anonymous (anonymous@undisclosed.example.com) — 2022-06-11T13:44:06+00:00

Show hardware information of system disks (manufacturer, etc...) # install the package apt install lshw # show the info lshw -class disk

get_rotational

Anonymous (anonymous@undisclosed.example.com) — 2020-02-29T16:51:38+00:00

Check a disk is HDD or SSD (rotational) You often get a new PC or laptop or using another person's computer and you may not know the disk technology being used (HDD/SSD). So, on linux you can use a sys kernel file to find it out. cat /sys/block/sda/queue/rotational # 0 means SSD, 1 means HDD # replace "sda" to your needs

grow_partition

Anonymous (anonymous@undisclosed.example.com) — 2021-05-05T07:12:55+00:00

Resize partition to grow the filesystem (useful on Virtual Environment Disks) There is some cases when you need to grow/enlarge a partition on a virtual disk (usually represented as /dev/vdX), here is how to do it rebooting once (yes, i would be better sysadmin if no reboot was needed

img_mount_loop

Anonymous (anonymous@undisclosed.example.com) — 2022-03-17T21:10:57+00:00

Mount .img partitions to separate loops so you can mount any partition inside image $ sudo kpartx -v -a file.iso add map loop0p1 (253:17): 0 8382464 linear 7:1 2048 $ mount /dev/mapper/loop0p1 ./mnt_point ... do something with the partition ... $ umount ./mnt_point $ kpartx -d -v file.iso del devmap : loop0p1 loop deleted : /dev/loop0

iscsi_update_targets

Anonymous (anonymous@undisclosed.example.com) — 2021-10-05T14:43:34+00:00

Update ISCSI target list from a certain ISCSI host In order to update targets of an iscsi host when adding a new one, run this command on the client: iscsiadm -m discovery -t sendtargets -p SERVER:3260

luks_change_key

Anonymous (anonymous@undisclosed.example.com) — 2020-05-08T16:01:20+00:00

Change passphrase on LUKS full encrypted disk/partition Simply changing your passphrase on a LUKS drive with only one passphrase is extremely easy. Open a terminal and run the following command, substituting the actual drive location for “sdX.” First, you’ll be prompted to enter your existing passphrase. Then, you can create a new one.

lvm_backup_restore

Anonymous (anonymous@undisclosed.example.com) — 2020-07-11T11:52:20+00:00

Backup and restore LVM configuration of a volume group (vg) To know the volume groups of your system, issue the following command, we will use the VG Name field: vgdisplay This command is automatically done everytime the LVM volume group changes, so you don't really have to schedule this command, but if you want to make sure you have a

mount_gz_image

Anonymous (anonymous@undisclosed.example.com) — 2023-04-25T22:48:32+00:00

Mount a .gz compressed image file using nbdkit and nbd-client (read-only) # create the server that decompresses the file live nbdkit -i 127.0.0.1 /usr/lib/(your-machine-arch)/nbdkit/plugins/nbdkit-gzip-plugin.so file=test.img.gz # connect to the server and create a device interface on /dev/nbd0 nbd-client 127.0.0.1 10809 /dev/nbd0 # once finished, you can clean-up everything by: nbd-client --disconnect /dev/nbd0 pkill nbdkit

physical_disk_resize

Anonymous (anonymous@undisclosed.example.com) — 2022-05-26T11:49:51+00:00

Resize virtual disk (vdX) to match it's new size (growpart, resize2fs) Given that the device is /dev/vda and the system partition (/) is at /dev/vda1, we run this commands: growpart /dev/vda 1 resize2fs /dev/vda1 The code on LVM changes a bit

shred_ssd

Anonymous (anonymous@undisclosed.example.com) — 2023-03-12T19:06:34+00:00

Securely erase an SSD with hdparm SSD drives need different way of erasing data. We will cover how to do this on Linux without proprietary software. # show drive Infos and lock for "frozen" state!!! shoud be not frozen/locked hdparm -I /dev/sdb # if frozen, try the following: systemctl suspend # then, unsuspend. It should be "not frozen" after that # now, erase the data hdparm --security-set-pass NULL /dev/sdb # set the "NULL" password to UNLOCK the Controller hdparm --security-erase NULL /…

t2fs_labelname

Anonymous (anonymous@undisclosed.example.com) — 2020-02-07T11:27:21+00:00

Change ext3/ext4 disk label name tune2fs -L LABEL_NAME /dev/XXX

t2fs_reserved

Anonymous (anonymous@undisclosed.example.com) — 2020-02-07T11:25:41+00:00

Remove reserved blocks from an ext4 partition Where XXX is your device (partition or not): tune2fs -m 0 /dev/XXX

uuid_set_device

Anonymous (anonymous@undisclosed.example.com) — 2020-08-24T16:52:41+00:00

Manually set UUID of Linux swap/ext partition using cli Set UUID to a swap file/device swaplabel -U 427ec4fa-e8e5-47a5-af4c-e15583aeadd7 /dev/sdb5 Set UUID to an ext3/ext4 partition tune2fs -U 95a40ae4-3f84-6ea1-bee3-7ad41ef76443 /dev/sdb1

write_iso_to_dvd

Anonymous (anonymous@undisclosed.example.com) — 2020-05-24T21:15:16+00:00

Write/Burn an .ISO image file to a dvd-rw Burn an installation .iso image into a dvd rw device apt install growisofs growisofs -Z /dev/dvd=file.iso