pi@basar3-85:~ $ mariabackup --user=[user-replaced] --password=[pw-replaced] --backup --target-dir=/home/pi/backuptest-export.sql

[00] 2021-04-17 12:26:12 Connecting to MySQL server host: localhost, user: [replaced, root access], password: set, port: not set, socket: /var/run/mysqld/mysqld.sock

[00] 2021-04-17 12:26:12 Using server version 10.3.27-MariaDB-0+deb10u1

mariabackup based on MariaDB server 10.3.27-MariaDB debian-linux-gnueabihf (armv8l)

[00] 2021-04-17 12:26:12 uses posix_fadvise().

[00] 2021-04-17 12:26:12 cd to /var/lib/mysql/

[00] 2021-04-17 12:26:12 open files limit requested 0, set to 1024

[00] 2021-04-17 12:26:12 mariabackup: using the following InnoDB configuration:

[00] 2021-04-17 12:26:12 innodb_data_home_dir = 

[00] 2021-04-17 12:26:12 innodb_data_file_path = ibdata1:12M:autoextend

[00] 2021-04-17 12:26:12 innodb_log_group_home_dir = ./

[00] 2021-04-17 12:26:12 InnoDB: Using Linux native AIO

2021-04-17 12:26:12 0 [Note] InnoDB: Number of pools: 1

2021-04-17 12:26:12 0 [Warning] InnoDB: Unable to open "./ib_logfile0" to check native AIO read support.

2021-04-17 12:26:12 0 [Warning] InnoDB: Linux Native AIO disabled.

2021-04-17 12:26:12 0 [ERROR] InnoDB: Operating system error number 13 in a file operation.

2021-04-17 12:26:12 0 [ERROR] InnoDB: The error means mysqld does not have the access rights to the directory.

2021-04-17 12:26:12 0x76f5d210  InnoDB: Assertion failure in file /build/mariadb-10.3-S9bYSW/mariadb-10.3-10.3.27/storage/innobase/fil/fil0fil.cc line 671

InnoDB: Failing assertion: success

InnoDB: We intentionally generate a memory trap.

InnoDB: Submit a detailed bug report to https://jira.mariadb.org/

InnoDB: If you get repeated assertion failures or crashes, even

InnoDB: immediately after the mysqld startup, there may be

InnoDB: corruption in the InnoDB tablespace. Please refer to

InnoDB: https://mariadb.com/kb/en/library/innodb-recovery-modes/

InnoDB: about forcing recovery.

210417 12:26:12 [ERROR] mysqld got signal 6 ;

This could be because you hit a bug. It is also possible that this binary

or one of the libraries it was linked against is corrupt, improperly built,

or misconfigured. This error can also be caused by malfunctioning hardware.

To report this bug, see https://mariadb.com/kb/en/reporting-bugs

We will try our best to scrape up some info that will hopefully help

diagnose the problem, but since we have already crashed, 

something is definitely wrong and this may fail.

Server version: 10.3.27-MariaDB-0+deb10u1

key_buffer_size=0

read_buffer_size=131072

max_used_connections=0

max_threads=1

thread_count=0

It is possible that mysqld could use up to 

key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 4390 K  bytes of memory

Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x0

Attempting backtrace. You can use the following information to find out

where mysqld died. If you see no messages after this, something went

terribly wrong...

stack_bottom = 0x0 thread_stack 0x49000

The manual page at https://mariadb.com/kb/en/how-to-produce-a-full-stack-trace-for-mysqld/ contains

information that should help you find out what is causing the crash.

Writing a core file...

Working directory at /var/lib/mysql

Resource Limits:

Limit                     Soft Limit           Hard Limit           Units     

Max cpu time              unlimited            unlimited            seconds   

Max file size             unlimited            unlimited            bytes     

Max data size             unlimited            unlimited            bytes     

Max stack size            8388608              unlimited            bytes     

Max core file size        0                    unlimited            bytes     

Max resident set          unlimited            unlimited            bytes     

Max processes             6873                 6873                 processes 

Max open files            1024                 1048576              files     

Max locked memory         67108864             67108864             bytes     

Max address space         unlimited            unlimited            bytes     

Max file locks            unlimited            unlimited            locks     

Max pending signals       6873                 6873                 signals   

Max msgqueue size         819200               819200               bytes     

Max nice priority         0                    0                    

Max realtime priority     0                    0                    

Max realtime timeout      unlimited            unlimited            us        

Core pattern: core

Abgebrochen

pi@basar3-85:~ $ 

#

# These groups are read by MariaDB server.

# Use it for options that only the server (but not clients) should see

# this is read by the standalone daemon and embedded servers

[server]

port	=	{{ mariadb_port }}

# this is only for the mysqld standalone daemon

[mysqld]

#

# * Basic Settings

#

user                    = mysql

pid-file                = /run/mysqld/mysqld.pid

basedir                 = /usr

datadir                 = /var/lib/mysql

tmpdir                  = /tmp

lc-messages-dir         = /usr/share/mysql

lc-messages             = en_US

skip-external-locking

# Broken reverse DNS slows down connections considerably and name resolve is

# safe to skip if there are no "host by domain name" access grants

#skip-name-resolve

# Instead of skip-networking the default is now to listen only on

# localhost which is more compatible and is not less secure.

bind-address            = 127.0.0.1

#

# * Fine Tuning

#

#key_buffer_size        = 128M

#max_allowed_packet     = 1G

#thread_stack           = 192K

#thread_cache_size      = 8

# This replaces the startup script and checks MyISAM tables if needed

# the first time they are touched

#myisam_recover_options = BACKUP

#max_connections        = 100

#table_cache            = 64

#

# * Logging and Replication

#

# Both location gets rotated by the cronjob.

# Be aware that this log type is a performance killer.

# Recommend only changing this at runtime for short testing periods if needed!

# general_log_file       = /var/log/mysql/mysql.log

# general_log            = 1

# When running under systemd, error logging goes via stdout/stderr to journald

# and when running legacy init error logging goes to syslog due to

# /etc/mysql/conf.d/mariadb.conf.d/50-mysqld_safe.cnf

# Enable this if you want to have error logging into a separate file

log_error = /var/log/mysql/error.log

# Enable the slow query log to see queries with especially long duration

#slow_query_log_file    = /var/log/mysql/mariadb-slow.log

#long_query_time        = 10

#log_slow_verbosity     = query_plan,explain

#log-queries-not-using-indexes

#min_examined_row_limit = 1000

# The following can be used as easy to replay backup logs or for replication.

# note: if you are setting up a replication slave, see README.Debian about

#       other settings you may need to change.

#server-id              = 1

#log_bin                = /var/log/mysql/mysql-bin.log

expire_logs_days        = 10

#max_binlog_size        = 100M

#

# * SSL/TLS

#

# For documentation, please read

# https://mariadb.com/kb/en/securing-connections-for-client-and-server/

#ssl-ca = /etc/mysql/cacert.pem

#ssl-cert = /etc/mysql/server-cert.pem

#ssl-key = /etc/mysql/server-key.pem

#

# * Character sets

#

# MySQL/MariaDB default is Latin1, but in Debian we rather default to the full

# utf8 4-byte character set. See also client.cnf

character-set-server  = utf8mb4

collation-server      = utf8mb4_general_ci

#

# * InnoDB

#

# InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/.

# Read the manual for more InnoDB related options. There are many!

# Most important is to give InnoDB 80 % of the system RAM for buffer use:

# https://mariadb.com/kb/en/innodb-system-variables/#innodb_buffer_pool_size

#innodb_buffer_pool_size = 8G

# this is only for embedded server

[embedded]

# This group is only read by MariaDB servers, not by MySQL.

# If you use the same .cnf file for MySQL and MariaDB,

# you can put MariaDB-only options here

[mariadb]

#ssl = 1

#ssl_cert = /etc/mysql/cert/server-cert.pem

#ssl_key =  /etc/mysql/cert/server-key.pem

#ssl_ca =   /etc/mysql/cert/ca-cert.pem

# This group is only read by MariaDB-10.5 servers.

# If you use the same .cnf file for MariaDB of different versions,

# use this group for options that older servers don't understand

[mariadb-10.5]