Blog rafroma

Reducing the size of a QEMU virtual disk (thin disk)

On all mounting points
dd if=/dev/zero of=/nul;sync;sync;sync;rm -f /nul;sync

Stop VM

Convert disk

qemu-img convert -O qcow2 -c disk1.qcow disk1.new.qcow

AC power notify

upower -i $(upower -e | grep '_AC') | grep "online"

mysql repair all tables

mysqlcheck -u root -p --auto-repair --check --all-databases

Unboud (DNS) – listen on IPv4 only

Add to /etc/unbound/unbound.conf

server:
interface: 0.0.0.0

TMUX

split-window -h: Ctrl+b %

split-window -v: Ctrl+b ”

wrong Video codec on Opera Linux Mint

install chromium and

mv /usr/lib/x86_64-linux-gnu/opera/libffmpeg.so /usr/lib/x86_64-linux-gnu/opera/libffmpeg.so.orig
ln -s /usr/lib/chromium/libffmpeg.so /usr/lib/x86_64-linux-gnu/opera/

MSSQL restore all databases from folder with .bak files

Powershell

Install-Module dbatools
Import-Module dbatools
Set-DbatoolsInsecureConnection -SessionOnly
Restore-DbaDatabase -SqlInstance SERVER-NAME\INSTANCE-NAME -Path 'C:\PATH-TO-BACKUPS'

MSSQL: User, group, or role ‘platnik’ already exists in the current database.

lists logins and incorrect SIDs
USE <platnik_db>
GO
EXEC sp_change_users_login 'Report'
GO

Then start SQL
USE <platnik_db>
GO
EXEC sp_change_users_login 'Auto_Fix','<user_name>',NULL, '<password>'
GO

Delete multiple databases in MSSQL

drop databases query

USE master;
Go
SELECT 'DROP DATABASE ['+ name + ']'
FROM sys.databases WHERE name like 'PREFIX%';
GO

snapshots of UEFI libvirt-based (KVM) virtual machines

Shut down VM and then

Listing
qemu-img snapshot -l <file>.qcow2

Create
qemu-img snapshot -c <snap-name> <file>.qcow2

Revert to 
qemu-img snapshot -a <snap-name> <file>.qcow2

Delete
qemu-img snapshot -d <snap-name> <file>.qcow2