Managing storage devices Flashcards
What is NVDIMMN
non-volatile dual in-line memory modules
combo of memory and storage.
What are the different remote storage options?
iSCSI
FC (fiber channel)
NVMe (non-volatile memory express)
Interface that allows host software utility to communicate with ssd drives.
Device Mapper multipathing (DM Multipath)
Network File Systems
NFS
SMB
3.1 How many partitions does MBR have vs GPT?
MBR
either
4 primary
or
3 primary and one extended that has multiple logical patitions
Can only hand storage up to 2 TiB
GPT
128 partitions
Can handle storage up to 64ZiB
What does active mean in terms of a partition
OS in the partition is that’s marked active is booted
Describe an extended partition
Has it’s own partition table.
No fixed amount of logical partitions except Linux only allows 15 max.
Partition naming scheme
/dev/xxyN
/dev <- it’s a device
xx <- Type of device
y <- specific device (sda and sdb)
N <- which partition
If you have more than 26 they’ll start looking like this
sdaa1
If you mounted partition sda2 on /usr,every child directory would be part of that partition. Could you mount another partition onto a child directory of /usr?
yes
Make an MBR partition table on sda
from there, look at sdb, see if it’s used for LVM, raid, swap, hidden, root, or boot
parted /dev/sda
print
mklabel msdos (gpt for gpt lel)
print
select /dev/sdb
look at flags
quit
Create a partition that’s primary, and is 1G in size
4.3
parted /dev/sda
mkpart primary xfs 1024MiB 2048MiB
udevadm settle (registers the new device node?)
Check to see if a device is using GPT or MBR
fdisk -l
look at:
Disk Label Type: dos = MBR
Resize /dev/sda2
parted /dev/sda
print (find minor number and current ending point)
resizepart 1 2Gib
Minor number just means partition number.
cat /proc/partitions
Remove a partition on /dev/sda
Regenerate mount units
See active kernel options for any reference (if swap or lvm)
parted /dev/sda
print
rm 2
print
quit
cat /proc/partitions
if deleted in /etc/fstab, regenerate mounts
systemctl daemon-reload
grubby –info=ALL
grubby –update-kernel=ALL –remove-args=”option”
dracut –force –verbose (register changes in early boot system)
File System Identifiers vs Device Identifiers
File System Identifiers:
Tied to a file system created on a block device. So if you rewrite device with mkfs, this will be lost:
UUID - Unique Identifier
Label
Device Identifier:
Tied to a block device like a disk or partition. This means you can rewrite and it will be fine:
WWID - World Wide Identifier
Partition UUID
Serial Number
TIP - LVMs use lots of devices, so it’s better using a file system identifier here
Path that uuids stored
Path where labels are stored
Path where WWID stored
Path where partition UUIDs stored (defined biy GPT part table)
Path where path is stored (symb name that refers to storage device by hardware path)
/dev/disk/by-uuid/
fstab:
UUID=2948u149iut98egq9i2t
/dev/disk/by-label/
fstab:
LABEL=boot
/dev/disk/by-id
/dev/disk/by-partuuid
/dev/disk/by-path/
List UUID and Labels of /dev/sda
lsblk –fs /dev/sda
