====== Linux storage ======

This page contains my personal notes on Linux filesystems, partitioning, backups, performance tuning, and related concepts.  **Warning:** //these notes are specific to my own non-critical systems and may not be applicable in general use cases.//

> **Update:** Due to a a number of stability issues I've returned to using [[https://neon.kde.org/|KDE neon]] on my work laptop.  Nod to the KDE devs for maintaining a stable rolling release distro.  The general principles still apply to any modern distro.

===== Partitioning for Ubuntu 19.04 workstations =====

I'm currently the following configuration on my Dell Precision 5520 notebook computer:

  * 256GB NVMe drive
  * 256MiB EFI partition as a raw FAT partition
  * 512MiB /boot partition as a raw ext4 partition
  * the rest of the disk is configured as an LVM PV consuming 92% of the drive
  * this currently contains one volume group with two logical volumes, 16GiB for swap (to allow hibernate) and the remaining space is used for /

==== Initializing partitions using gparted ====

GNU parted manual: https://www.gnu.org/software/parted/manual/parted.html#Using-Parted-1

<file sh>
parted /dev/nvme0n1
print # check to see what's already on the disk before you do anything else
mklabel gpt
unit MiB # use binary format units when partitioning
mkpart efi fat32 1MiB 257MiB # align the first block
mkpart boot ext4 257MiB 769MiB
mkpart lvm-pv0 ext4 769MiB 92% # finish the LVM pv at 92% capacity
</file>

If this worked you will see something like this when you print the partition table

<file sh>
(parted) print                                                            
Model: PC401 NVMe SK hynix 256GB (nvme)
Disk /dev/nvme0n1: 256GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: 

Number  Start   End    Size   File system  Name     Flags
 1      1049kB  269MB  268MB  ext4         efi      msftdata
 2      269MB   806MB  537MB               boot
 3      806MB   236GB  235GB               lvm-pv0  lvm
</file>

As far as I can tell parted can't label volumes as Linux LVM, so I do that using fdisk.

<file sh>
root@kubuntu:~# fdisk /dev/nvme0n1

Welcome to fdisk (util-linux 2.33.1).                                                   
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.


Command (m for help): t
Partition number (1-3, default 3): 3
Partition type (type L to list all types): 31

Changed type of partition 'Linux filesystem' to 'Linux LVM'.

Command (m for help): p
Disk /dev/nvme0n1: 238.5 GiB, 256060514304 bytes, 500118192 sectors
Disk model: PC401 NVMe SK hynix 256GB               
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: 14779AE7-C2BB-4F6A-9F6E-A927FAF7AAFB

Device           Start       End   Sectors   Size Type
/dev/nvme0n1p1    2048    526335    524288   256M Microsoft basic data
/dev/nvme0n1p2  526336   1574911   1048576   512M Linux filesystem
/dev/nvme0n1p3 1574912 460107775 458532864 218.7G Linux LVM

Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.
</file>

=== Create filesystems and LVM structure ===

<file sh>
pvcreate /dev/nvme0n1p3
vgcreate vg0 /dev/nvme0n1p3
lvcreate -n swap0 -L 16GiB vg0
lvcreate -n root -l 100%FREE vg0
</file>

If you did this correctly you should see the following

<file sh>
lvs
  LV    VG  Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root  vg0 -wi-a----- 202.64g                                                    
  swap0 vg0 -wi-a-----  16.00g
</file>