Clickhouse-disks

A utility providing filesystem-like operations for ClickHouse disks. It can work in both interactive and not interactive modes.

Program-wide options

• --config-file, -C -- path to ClickHouse config, defaults to /etc/clickhouse-server/config.xml.
• --save-logs -- Log progress of invoked commands to /var/log/clickhouse-server/clickhouse-disks.log.
• --log-level -- What type of events to log, defaults to none.
• --disk -- what disk to use for mkdir, move, read, write, remove commands. Defaults to default.
• --query, -q -- single query that can be executed without launching interactive mode
• --help, -h -- print all the options and commands with description

Lazy initialization

All disks which are available in config are initialized lazily. This means that the corresponding object for a disk is initialized only when corresponding disk is used in some command. This is done to make the utility more robust and to avoid touching of disks which are described in config but not used by a user and can fail during initialization. However, there should be a disk which is initialized at the clickhouse-disks launch. This disk is specified with parameter --disk through command-line (default value is default).

Default Disks

After launching, there are two disks that are not specified in the configuration but are available for initialization.

1. local Disk: This disk is designed to mimic the local file system from which the clickhouse-disks utility was launched. Its initial path is the directory from which clickhouse-disks was started, and it is mounted at the root directory of the file system.

2. default Disk: This disk is mounted to the local file system in the directory specified by the clickhouse/path parameter in the configuration (the default value is /var/lib/clickhouse). Its initial path is set to /.

Clickhouse-disks state

For each disk that was added the utility stores current directory (as in a usual filesystem). User can change current directory and switch between disks.

State is reflected in a prompt "disk_name:path_name"

Commands

In these documentation file all mandatory positional arguments are referred as <parameter>, named arguments are referred as [--parameter value]. All positional parameters could be mentioned as a named parameter with a corresponding name.

• cd (change-dir, change_dir) [--disk disk] <path> Change directory to path path on disk disk (default value is a current disk). No disk switching happens.
• copy (cp) [--disk-from disk_1] [--disk-to disk_2] <path-from> <path-to>. Recursively copy data from path-from at disk disk_1 (default value is a current disk (parameter disk in a non-interactive mode)) to path-to at disk disk_2 (default value is a current disk (parameter disk in a non-interactive mode)).
• current_disk_with_path (current, current_disk, current_path) Print current state in format: Disk: "current_disk" Path: "current path on current disk"
• help [<command>] Print help message about command command. If command is not specified print information about all commands.
• move (mv) <path-from> <path-to>. Move file or directory from path-from to path-to within current disk.
• remove (rm, delete) <path>. Remove path recursively on a current disk.
• link (ln) <path-from> <path-to>. Create a hardlink from path-from to path-to on a current disk.
• list (ls) [--recursive] <path> List files at paths on a current disk. Non-recursive by default.
• list-disks (list_disks, ls-disks, ls_disks). List disks names.
• mkdir [--recursive] <path> on a current disk. Create a directory. Non-recursive by default.
• read (r) <path-from> [--path-to path] Read a file from path-from to path (stdout if not supplied).
• switch-disk [--path path] <disk> Switch to disk disk on path path (if path is not specified default value is a previous path on disk disk).
• write (w) [--path-from path] <path-to>. Write a file from path (stdin if path is not supplied, input must finish by Ctrl+D) to path-to.