Storage Flashcards
Where are block device file stored?
/dev
What is the first detected the first detected SATA, SAS, SCSI, or USB hard drive?
/dev/sda
What is the second detected the first detected SATA, SAS, SCSI, or USB hard drive?
/dev/sdb
What name is given to virtio-blk paravirtualized storage (VMs) device storage?
/dev/vda, /dev/vdb, /dev/vdc, etc.
How do you recognize block devices on the file system?
ls -l /dev/sda1
Any entry with file type b is a block device.
brw-rw—-. 1 root disk 8, 1 Feb 22 08:00 /dev/sda1
display an overview of local and remote file-system devices
df
View the file systems on the host machine with all units converted to human-readable format
df -h
View the disk usage report for the /usr/share directory
du /usr/share
Which command provides an overview of the file-system mount points and the available free space in SI units?
df -H
What is the naming pattern for ssd storage devices?
/dev/nvme0, /dev/nvme1, …
What is the naming pattern for SD storage devices?
/dev/mmcblk0, /dev/mmcblk1, …
list the details of a specified block device or of all the available devices
lsblk
mount the /dev/vda4 partition on the /mnt/data mount point
mount /dev/vda4 /mnt/data
Mount the file system by the file-system UUID.
mount UUID=”efd314d0-b56e-45db-bbb3-3f32ae98f652” /mnt/data
Determine the UUID of a file system
lsblk -fp
lsblk -o NAME,UUID
unmount a file system
umount /mnt/data
identify which processes are preventing the file system from successfully unmounting
lsof /mnt/data
How often is the locate db updated?
everyday
force the locate database to update itself immediately?
updatedb
Difference between locate and find
locate searches a pre-generated index and returns the results instantly (fast, index update delay).
find searches for files in real time by parsing the file-system hierarchy (slow, accurate).
Example uses of locate
locate image
locate -i passwd
locate -n 5 file.txt
search files with case-insensitive text that matches the messages string in their names in the root / directory,
find / -iname ‘messages’
search for files that the developer user owns
find -user developer
search for files that the developer group owns
find -group developer
search for files that the 1000 user ID owns
find -uid 1000
lists files that the root user owns and with the mail group
find / -user root -group mail
find file by permission
find /home -perm 764
find /home -perm u=rwx,g=rw,o=r
find file by permission while showing file details
find /home -perm 764 -ls
search for files for which the user has read permissions, OR the group has at least read permissions, OR others have at least write permission
find /home -perm /442
find /home -perm /u=r,g=r,o=w
search for files for which the user has at least write and execute permissions, AND the group has at least write permission, AND others have at least read permission
find /home -perm -324
find /home -perm -u=wx,g=w,o=r
search for any file for which others have at least read access
find -perm -004
find -perm -o=r
search for files with a size of more than 10 gigabytes
find -size +10G
search for files with an exact size of 10 megabytes
find -size 10M
search for files with a size of less than 10 kilobytes
find -size -10k
search for all files with content that changed 120 minutes ago
find / -mmin 120
search for all files with content that changed more than 200 minutes ago
find / -mmin +200
lists files that changed less than 150 minutes ago
find / -mmin -150
Search for all directories in the /etc directory
find /etc -type d
Search for all soft links in the / directory
find / -type l
Search for all block devices in the /dev directory
find /dev -type b
Search for all regular files with more than one hard link
find / -type f -links +1
What are tools for disk and partition management?
1) Web console
2) ansible
3) fdisk
4) gdisk
5) parted
MBR
1) Legacy
2) 2 TiB disk and partition size limit
3) Max of 4 primary partitions
4) Suitable for old BIOS Firmware
5) 15 partitions max
6) 32 bits
GPT
1) Unified Extensible Firmware Interface (UEFI) firmware
2) eight zebibytes (ZiB) or eight billion tebibytes (TiB) size limit
3) 128 partitions max
4) 64 bits
Enable storage in cockpit
dnf install cockpit-storaged
standard partition editor on rhel
parted
what partitioning does parted support?
MBR and GPT
display the partition table on /dev/vda with parted
parted /dev/vda print
Configure new mbr disk with parted
parted /dev/vdb mklabel msdos
parted /dev/vdb mkpart primary 2048s 1001MB
udevadm settle
mkfs.xfs /dev/vdb1
virtual memory
swap + RAM
format a partition for swap
mkswap /dev/vdb2
Activate swap on /dev/vdb2
swapon /dev/vdb2
swap file system type
linux-swap
Configure new GPT disk with parted
parted /dev/vdb mklabel gpt
parted /dev/vdb mkpart mydisk 2048s 1001MB
udevadm settle
mkfs.xfs /dev/vdb1
