Clickhouse Desk: March 2026

Monday, March 16, 2026

Issue trying to back up the clickhouse database

While trying to issue a backup database statement and receiving the following error.

Code: 627. DB::Exception: Received from localhost:9000. DB::Exception: Not found backup engine 'DISK'. (BACKUP_ENGINE_NOT_FOUND)

backup database test to DISK('backups','test_1');

BACKUP DATABASE test TO DISK('backups', 'test_1')
Query id: 19a96e04-a9f9-408a-956c-d1a60a72fe82
Elapsed: 0.050 sec. 
Received exception from server (version 26.2.4):
Code: 627. DB::Exception: Received from localhost:9000. DB::Exception: Not found backup engine 'DISK'. (BACKUP_ENGINE_NOT_FOUND)

Added new entry into /etc/clickhouse-server/config.d/ and restarted the clickhouse-server.

<clickhouse>
<storage_configuration>
<disks>
<backups>
<type>local</type>
<path>/var/lib/clickhouse/backups/</path>
</backups>
</disks>
</storage_configuration>
<backups>
<allowed_disk>backups</allowed_disk>
<allowed_path>/var/lib/clickhouse/backups/</allowed_path>
</backups>
</clickhouse>

Resolution.

It turns out the disk is case sensitive as Disk.

BACKUP DATABASE test TO disk('backups', 'test_database_backup_1');

BACKUP DATABASE test TO disk('backups', 'test_database_backup_1')
Query id: a9867d40-6965-4ac5-b722-2dc90bb5bc71
Elapsed: 0.003 sec. 
Received exception from server (version 26.2.4):
Code: 627. DB::Exception: Received from localhost:9000. DB::Exception: Not found backup engine 'disk'. (BACKUP_ENGINE_NOT_FOUND)

Test with "Disks"

BACKUP DATABASE test TO Disks('backups', 'test_database_backup_1');

BACKUP DATABASE test TO Disks('backups', 'test_database_backup_1')
Query id: def1034e-872c-4563-895c-cdde4df4b222
Elapsed: 0.037 sec. 
Received exception from server (version 26.2.4):
Code: 627. DB::Exception: Received from localhost:9000. DB::Exception: Not found backup engine 'Disks'. (BACKUP_ENGINE_NOT_FOUND)

Test with Disk

Successful !

BACKUP DATABASE test TO Disk('backups', 'test_database_backup_1');

BACKUP DATABASE test TO Disk('backups', 'test_database_backup_1')
Query id: ca4a9b80-0193-4139-b79c-116df0990b4d
┌─id───────────────────────────────────┬─status────────┐
1. │ b2899464-7b17-48f6-92d0-933db17f5b44 │ BACKUP_CREATED │
└──────────────────────────────────────┴──────────────┘

1 row in set. Elapsed: 0.006 sec.

sudo ls -las /var/lib/clickhouse/backups/test_database_backup_1
total 16
4 drwxr-x--- 3 clickhouse clickhouse 4096 Mar 14 15:42 .
4 drwxr-x--- 3 clickhouse clickhouse 4096 Mar 14 15:42 ..
4 -rw-r----- 1 clickhouse clickhouse 300 Mar 14 15:42 .backup
4 drwxr-x--- 2 clickhouse clickhouse 4096 Mar 14 15:42 metadata

Test backup with Disk("xxx",)

backup database test to Disk('xxx','test_1');

BACKUP DATABASE test TO Disk('xxx', 'test_1')
Query id: a42ffb06-883a-41c6-a3aa-09a750980014
Elapsed: 0.008 sec.
Received exception from server (version 26.2.4):
Code: 36. DB::Exception: Received from localhost:9000. DB::Exception: Disk ''xxx'' is not allowed for backups, see the 'backups.allowed_disk' configuration parameter. (BAD_ARGUMENTS)

Test back with "Disk"

backup database test to Disk('backups','test_1');

BACKUP DATABASE test TO Disk('backups', 'test_1')

Query id: 3b527b9d-08a4-43cd-b80c-ff39d265bfcd
┌─id───────────────────────────────────┬─status─────────┐
1. │ 23d072bd-cf1a-46d0-9417-1e252e59851a │ BACKUP_CREATED │
└──────────────────────────────────────┴───────────────┘

1 row in set. Elapsed: 0.004 sec.

Point of Reference

https://github.com/ClickHouse/ClickHouse/issues/54966

Friday, March 13, 2026

Failed to start clickhouse server with error that service did not take the steps required by its unit configuration.

Attempting to start clickhouse server this morning and immediately receiving this error.

sudo service clickhouse-server start

Job for clickhouse-server.service failed because the service did not take the steps required by its unit configuration.

See "systemctl status clickhouse-server.service" and "journalctl -xeu clickhouse-server.service" for details.

Error

/var/log/clickhouse-server/clickhouse-server.err.log

2026.03.13 13:27:23.755894 [ 133253 ] {} <Error> Application: Code: 210. DB::Exception: Listen [::]:9009 failed: Poco::Exception. Code: 1000, e.code() = 0, DNS error: EAI: Address family for hostname not supported (version 26.2.4.23 (official build)). (NETWORK_ERROR), Stack trace (when copying this message, always include the lines below):

Google Search came up with this.

The EAI: Address family for hostname not supported error in ClickHouse usually means that IPv6 is disabled on your server's operating system, but ClickHouse is configured to listen on an IPv6 address by default.

Resolution

/etc/clickhouse-server/config.d/listen.xml

<listen_host>0.0.0.0</listen_host>

</clickhouse>

Retried and successful. The status is Active

sudo service clickhouse-server start

sudo service clickhouse-server status|grep Active

Active: active (running) since Fri 2026-03-13 13:28:02 MDT; 25min ago

system.query_log does not existed in the Clickhouse Quick Install

It seems to be the Quick Install does not contain the system.query_log table. The config.xml does not have the entry within and even inserted the query_log section. Restarted the ClickHouse server, the table still does not appear. Did the SYSTEM FLUSH LOGS and that did not trigger the creation of the table as well.

SELECT name, value FROM system.settings WHERE name LIKE 'log_queries'
┌─name────────┬─value─┐
│ log_queries │ 1 │
└───────────┴─────┘

Inserted the following according to what has been suggested by the Clickhouse blog, and it did not trigger the query_log table creation.

https://github.com/ClickHouse/ClickHouse/issues/11194

<query_log>
<database>system</database>
<table>query_log</table>
<engine>Engine = MergeTree PARTITION BY event_date ORDER BY event_time TTL event_date + INTERVAL 30 day</engine>
<flush_interval_milliseconds>7500</flush_interval_milliseconds>
<max_size_rows>1048576</max_size_rows>
<reserved_size_rows>8192</reserved_size_rows>
<buffer_size_rows_flush_threshold>524288</buffer_size_rows_flush_threshold>
<flush_on_crash>false</flush_on_crash>
</query_log>

However, the full install do contain the system.query_log table by default.

https://clickhouse.com/docs/install/debian_ubuntu

I think this could be the reason. The Quick Install (https://clickhouse.com/docs/install/quick-install-curl) starts up Clickhouse with ./clickhouse server. While looking at the ps -ef|grep clickhouse, it does not associate to the config.xml file.

While with the full install, the Clickhouse started with the (sudo service clickhouse-server start) and ps -ef|grep clickhouse apparently has the config.xml associated with. Upon validating the config.xml, it does the have the query_log block. So, in the case of a Quick Install, the startup will have to call (./clickhouse server -C flag) In order to have the query_log created during the start up, the config.xml will need the query_log section.

shimano@shimano-VirtualBox:~$ ps -ef|grep clickhouse
clickho+ 133853 1 0 13:27 ? 00:00:00 clickhouse-watchdog --config=/etc/clickhouse-server/config.xml --pid-file=/run/clickhouse-server/clickhouse-server.pid
clickho+ 133861 133853 48 13:27 ? 01:11:52 /usr/bin/clickhouse-server --config=/etc/clickhouse-server/config.xml --pid-file=/run/clickhouse-server/clickhouse-server.pid
shimano 137068 136336 0 15:56 pts/2 00:00:00 grep --color=auto clickhouse

This isn't necessarily an issue, but perhaps it needs documentation for the Quick Install on how to start up the ./clickhouse server with config.xml.

Thursday, March 12, 2026

Getting started with Clickhouse

Download Oracle's VirtualBox

https://www.virtualbox.org/

Alternatively, download

VMware Workdstation Pro, however, licensing state can be unstable throughout the

time.

Download Ubuntu

https://ubuntu.com/download/desktop

Install the Ubuntu ISO

From within the Ubuntu OS Download ClickHouse

https://clickhouse.com/support/platforms

I am using the Quick Install Guide

https://clickhouse.com/docs/install/quick-install-curl

How to ingest data into Clickhouse

https://clickhouse.com/docs/guides/inserting-data OR use the following but it takes awhile for 24 million rows of data insertion.

CREATE TABLE hackernews ENGINE = MergeTree ORDER BY tuple() AS
SELECT * FROM
url('https://datasets-documentation.s3.eu-west-3.amazonaws.com/hackernews/hacknernews.csv.gz',
'CSVWithNames'); Learning Resources Register Clickhouse Learning
https://learn.clickhouse.com/ https://clickhouse.com/docs/academic_overview