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P4 Server Administration Documentation | 2025.2

# Checkpoint files

A checkpoint A backup copy of the underlying metadata at a particular moment in time. A checkpoint can recreate db.user, db.protect, and other db.* files. See also metadata. is a file that contains the information necessary to fully restore the metadata Information that P4 Server maintains, such as who created file revisions in the depot, whether the file is a 'lazy copy,, the current state of client workspaces, protections, groups, users, labels, streams, and branches. Metadata is stored in the server database and is separate from the 'archive files' that users submit from their client workspace into the depot. in the P4 Server (`p4d`) database, such as changelists, branches, users, labels, protections, and jobs.

When you create a checkpoint, the metadata database is locked, enabling you to capture the internally-consistent state of that database at that point in time with transactional integrity. You can create a checkpoint while `p4d` is running. However, checkpointing can affect performance because all the database tables are locked while the command runs. You might want to schedule checkpointing to occur when the load from users is light.

To ensure that you have an incremental metadata backup between checkpoints, perform journal A file containing a record of every change made to the metadata since the time of the last checkpoint. This file grows as each transaction is logged. file rotation often. Consider whether weekly checkpoints and daily journal rotation might be appropriate for your organization. Regular checkpointing is important to keep the journal from getting too long. Making a checkpoint immediately before backing up your system is good practice. For more information about journal rotation, see Journal files.

## Checkpoints and versioned files

Checkpoints do not contain the content of versioned files Source files stored in the depot, including one or more revisions to each file. Also known as archive files, archives, and depot files. Versioned files typically use the naming convention 'filename,v' or '1.changelist.gz'., only the information required to restore the database of metadata. Versioned files need to be backed up using the utilities available for your operating system.

To guarantee database integrity upon restoration, the checkpoint must be as old as, or older than, the versioned files in the depot. This means that the server database must be checkpointed, and the checkpoint generation must be complete, before beginning the backup of the versioned files.

## Create a checkpoint

Checkpoints are not created automatically. Someone or something must run the checkpoint command on the P4 Server machine.

You can create a checkpoint by running:

     p4d -r serverRootDirectory -jc

Where `serverRootDirectory` overrides the default, which is the current working directory or `$P4ROOT` if set.

The resulting checkpoint file is also created in that same directory. (If that directory does not have the database files, they will be created.)

Because the purpose of the checkpoint (and journal) is to enable you to restore the server database, it is safer to store the checkpoint file in a different location than the server database.To customize the location and name of the checkpoint and journal files, see Use a prefix.

A checkpoint can also be created by using `p4 admin checkpoint`, which does not require a login account on the P4 Server machine.

For more details about options, see Checkpoint and journal options in P4 Server (p4d) reference.

### Checkpointing the central server

Most aspects of the checkpoint process are the same on all platforms. This table outlines the process for the central server The one server that is innermost in a multi-server deployment. In the server specification form field for Services, the central server might be specified as “standard” or “commit-server”. If edge servers are part of the multi-server deployment, the central server must be a commit server. See also 'upstream server'. and indicates where there are platform differences.

UNIX | Windows
--- | ---
When you run the command to create a checkpoint, `p4d` creates a checkpoint file named `checkpoint.n`, where `n` is the new value of the journal counter. You can also provide a journal prefix for `p4d -jc` or set the `journalPrefix` configurable to assign a location for rotated journals and checkpoints.
`p4d` renames the journal file to a file named `journal.n-1` in the `P4ROOT` directory. | `p4d` copies the journal file to a file named `journal.n-1` in the `P4ROOT` directory. On Windows, the default requires a copy and rename operation. To enable atomic rename, which might improve performance on Windows, set the `filesys.atomic.rename` configurable. Atomic rename is applicable to NTFS file systems where the journal and rotated journal are on the same disk volume.
Journals rotated to a different disk volume will be copied and renamed.
Providing a journal prefix for `p4d -jc` or setting the `journalPrefix` configurable allows you to set a prefix that is applied to checkpoint and rotated journal file names and that can specify the directory in which to store checkpoint and journal files.
`p4d` truncates the current journal so that, going forward, the current journal will not have any content that is older than the most recent checkpoint.
`p4d` writes the MD5 checksum of the checkpoint to a separate file, `checkpoint.n.md5`, and the `lastCheckpointAction` counter is updated to reflect successful completion. This can be used to verify that the associated checkpoint (`checkpoint.n`) has all the server metadata of the time the checkpoint was taken.
The workspace have list The list of file revisions most recently synced from the depot into the workspace. In other words, the list of files that the client workspace has. for a client workspace that is `readonly` or `partitioned` is neither journaled nor checkpointed. Consider using your system backup utilities if you have such clients.
When verifying the MD5 signature of a compressed checkpoint, the checkpoint must first be uncompressed into a form that reflects the line ending convention native to the system that produced the checkpoint:
LF line endings on UNIX | CR/LF line endings on Windows
You can verify the integrity of a checkpoint by using the `p4d -jv` command.

### Checkpointing and types of servers

Replicas, edge servers and standby servers cannot be checkpointed by using the `p4d -jc` command. Instead, use the `p4 admin checkpoint` command. This schedules checkpointing of the replicas, edge servers, and standby servers to occur when the target server The immediately upstream server for replica servers, edge servers, standby servers, proxies and brokers. See also 'upstream server' and 'central server'. performs its next journal rotation.

Distribution servers can be checkpointed with either the `p4d -jc` command or the `p4 admin checkpoint` command.

To create a checkpoint without being logged in to the P4 Server machine:

    p4 admin checkpoint [-z | -Z] [prefix]

### p4d -jc and p4 admin checkpoint

This table summarizes the use cases for two approaches to creating checkpoints.

p4d -jc | p4 admin checkpoint
--- | ---
For central servers The one server that is innermost in a multi-server deployment. In the server specification form field for Services, the central server might be specified as “standard” or “commit-server”. If edge servers are part of the multi-server deployment, the central server must be a commit server. See also 'upstream server'. and distribution servers | Must be used for replicas, edge servers, and standby servers but can be used for all server types.
Can be used by a system administrator who is logged in to the machine that runs P4 Server. This system administrator does not need to have a user account on P4 Server. | Can be run from a client machine or on the server machine. Only a P4 user with the access level of `super` or `operator` can run `p4 admin checkpoint` and `p4 admin journal`
Does not require P4 Server to be running. | Requires the user to be logged in to P4 Server, but this user does not need a login account to the machine on which P4 Server is running.

## Use a prefix

If no `prefix` is specified, `checkpoint.n` and `journal.n-1` are the default filenames.

To specify a prefix or directory location for the checkpoint and journal, use the `-jc` option. For example, you might create a checkpoint with:

    p4d -jc prefix

In this case,

- Your checkpoint files are named `prefix.ckp.n`, where `prefix` is as specified on the command line and `n` is a sequence number.

- Your journal files are named `prefix.jnl.n-1`, where

  - `prefix` is as specified on the command line.

  - `n-1` is a sequence number that is one less than the journal counter for the checkpoint number.

### A prefix can specify a directory

You can store checkpoints and journals in the directory of your choice by specifying the directory as part of the prefix. For example:

    p4d -r serverRootDirectory -J /path/to/journal -z -jc /path/to/checkpoints/mybackup

returns

    Checkpointing to /Users/bruges/server151/checkpoints/mybackup.ckp.299.gz...
    MD5 (/Users/bruges/server151/checkpoints/mybackup.ckp.299) = 5D7D8E548D080B16ECB66AD6CE0F2E5D
    Rotating journal to /Users/bruges/server151/checkpoints/mybackup.jnl.298.gz...

You can also specify the prefix for a server with:

    p4 configure set journalPrefix=prefix

Setting the `journalPrefix` configurable overrides the default name and directory for rotated journals and checkpoints. For an example, see `journalPrefix` in the P4 CLI Reference.

#### Multi-server and replicated environments

Setting the configurable for the journal prefix is a best practice for multi-server and replicated environments. For example, you might avoid confusion if you specify that an indicative term, such as "edge-London" or "standby-Paris", be part of the name.

## Automated checkpoints

You can set up an automated program to create your checkpoints on a regular schedule. Be sure to always check the program’s output to ensure that checkpoint creation was started. Compare the checkpoint’s actual MD5 checksum with that recorded in the `.md5` file, and back up the `.md5` file along with the checkpoint. After successful creation, a checkpoint file can be compressed, archived, or moved onto another disk. At that time or shortly thereafter, back up the versioned files stored in the depot subdirectories.

## Restore a database to an older checkpoint

The sequence numbers reflect the roll-forward nature of the journal. To restore the database to an older checkpoint, match the sequence numbers of the checkpoint and the journal A file containing a record of every change made to the metadata since the time of the last checkpoint. This file grows as each transaction is logged..

For example, to restore the state of P4 Server to what it was when `checkpoint.6` was taken, restore `checkpoint.5` and then load `journal.5` which contains all the changes made between `checkpoint.5` and `checkpoint.6`. In most cases, you only want to restore the current database, which is reflected by the highest-numbered `checkpoint.n` rolled forward with the changes in the current `journal`.

## If the checkpoint command fails

Checkpoint failure is usually a symptom of a resource problem that can put your database at risk if not handled correctly. If the checkpoint command fails, request assistance from the Perforce Support Center without delay.

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