Register or Edit a Physical Server

19 August 2025

Before registering a physical server with the Cohesity cluster, you must download and install the Cohesity agent on each server you plan to register.

Overview

Download the Cohesity agent to the physical server.
Install the agent on the physical server.

Instructions for silent installation on Windows servers are available here: Silently Install the Cohesity Agent on Windows Physical Servers.
Register the physical server with the Cohesity cluster.

Download and Install the Agent

Installing the agent on a physical server allows it to be registered as a source with the Cohesity cluster.

Select Data Protection > Sources.
Click Download Cohesity Agent.

Follow the installation instructions for the corresponding agent operating system:

Windows Agent

For Cohesity support information, see Physical Servers.

Ensure the agent has been downloaded to the server you want to protect.
As an administrator with local system privileges on that server, run the executable with Run as administrator and complete the installation wizard.

Install the Volume CBT (Changed Block Tracker) component to perform incremental backups. Installing this component requires a reboot. Without a reboot, only full backups can be performed. Not installing this component means only full backups can be performed.

The Cohesity Volume CBT driver creates the Cohesity_Bitmap.cty file at the root of each volume. There are multiple ways to backup Windows physical server but the Cohesity_Bitmap.cty file will be available on the system only if the Volume CBT driver is installed. This file is used to maintain the CBT data for incremental block-based backups across Windows server reboots.

Do not move or delete the “.cty” file.

The File System CBT (Changed Block Tracker) component is required for MS SQL file-based protection.

The agent starts automatically.

This installation does not require a restart. You can wait until a normal maintenance window (such as a Patch Tuesday) to restart. However, until you do, some Protection Groups that depend on Volume CBT will run in full backup mode.

Linux Agent

The Cohesity Linux agent is now available with different installer packages, providing support on multiple Linux distributions. The following table lists the installer packages and Linux distributions on which the installer package is supported.

Installer package	Linux distribution
(Default) RPM	RHEL and its derivative
SUSE RPM	SUSE
Script Installer	All supported Linux operating systems

For Cohesity support information, see Physical Servers.

Linux agent has dependencies on the following packages, which must be installed on the Linux server:

Command/Package	Linux distribution
Command/Package	RHEL	SUSE	CentOS	Ubuntu	Debian
rsync	rsync	rsync	rsync	rsync	rsync
mount	mount	mount	mount	mount	mount
lsof	lsof	lsof	lsof	lsof	lsof
umount	umount	umount	umount	umount	umount
cp	cp	cp	cp	cp	cp
chown	chown	chown	chown	chown	chown
chmod	chmod	chmod	chmod	chmod	chmod
mkdir	mkdir	mkdir	mkdir	mkdir	mkdir
rm	rm	rm	rm	rm	rm
tee	tee	tee	tee	tee	tee
hostname	hostname	hostname	hostname	hostname	hostname
stat	stat	stat	stat	stat	stat
blkid	blkid	blkid	blkid	blkid	blkid
ls	ls	ls	ls	ls	ls
losetup	losetup	losetup	losetup	losetup	losetup
dmsetup	dmsetup	dmsetup	dmsetup	dmsetup	dmsetup
timeout	timeout	timeout	timeout	timeout	timeout
lvs	lvs	lvs	lvs	lvs	lvs
vgs	vgs	vgs	vgs	vgs	vgs
lvcreate	lvcreate	lvcreate	lvcreate	lvcreate	lvcreate
lvremove	lvremove	lvremove	lvremove	lvremove	lvremove
lvchange	lvchange	lvchange	lvchange	lvchange	lvchange
libpcap-progs	null	libpcap-progs	null	null	null
nfs-utils Required for Instant Volume Mount, file-folder recovery from block-based backup and VMware backup.	nfs-utils	nfs-utils	nfs-utils	nfs-utils	nfs-utils
wget	wget	wget	wget	wget	wget

Installing the Linux agent as an LDAP user is supported.

Install RPM, Debian or SUSE RPM Installer Package

The following table explains the action to be performed for installing the RPM, Debian or SUSE installer package:

In the following commands, replace the Cohesity agent version with the desired agent version.

Action	How to
Download the Agent installer	From the Download Agents window, based on your Linux distribution, select RPM, Debian, or SUSE RPM and download it to the server you want to protect.
Navigate to the downloaded directory	As the root user with local system privileges on that server, change the directory to the location of the installer package.
Install the Custom certificates	LINUX If you are using a Cohesity certificate then run the following commands to install the user certificate followed by agent installation: export ENFORCE_USE_CUSTOM_CERTS=true && export AGENT_CERT_FILE=<path-to-agent-certificate-in-Cohesity-format>
Install the Agent	Run the following command depending on the installer package: RPM: `rpm -i el-cohesity-agent-7.3.2-1.x86_64.rpm` or `yum localinstall ./el-cohesityagent-7.3.2-1.x86_64.rpm` Debian: `dpkg -i cohesity-agent_7.3.2-1_amd64.deb` SUSE RPM: `rpm -i cohesity-agent-7.3.2-1.x86_64.rpm`
Install the agent as root user	Run the executable file with the following command syntax: /<path_to_installer_file> -- --install -c 0 -S root -G root Followings are the command options in details: -S this is the user to run the agent, specify root. -G this is the group permission the Agent will use for files and directories installed by the agent, specify root. -c this boolean switch controls if the OS user and group should be created. 0 means do not create the OS user and group, 1 means the agent installation will create the specified OS user and group. (When choose to run with the root user, specify ‘-c 0’ as ‘root’ already exists)
Install the agent as non-root user	To start the service as a non-root user, create a new user or use an existing user with sudo permission and run the following command: RPM: `export COHESITYUSER=<username> ; rpm -i el-cohesity-agent-7.3.2-1.x86_64` Debian: `COHESITYUSER=<username> dpkg -i cohesity-agent_7.3.2-1_amd64` SUSE RPM: `export COHESITYUSER=<username> rpm -i cohesity-agent-7.3.2-1.x86_64` Where, `<username>` is the user name with sudo permission. By default, the installation uses the root user permission for all the files, and the service is started as root. Therefore, it is required to add non-root users to the sudoers list by making the following changes in the `/etc/sudoers` file: `<user_name> ALL=(ALL) NOPASSWD:ALL` `Defaults:<user_name> !requiretty` An example of the sudoers file is as given below: dgoble ALL=(ALL) NOPASSWD:ALL Defaults:dgoble !requiretty cohbackup ALL=(ALL) NOPASSWD:ALL Defaults:cohbackup !requiretty You can add sudo privileges for non-root users using the syntax given below: `<user_name> ALL=(ALL) NOPASSWD:/path/to/command1, /path/to/command2, /path/to/command3` Remove `NOPASSWD` from the command above if you do not want to authenticate every sudo commands with password. The example below shows the sudo commands for user cohesityagent: cohesityagent ALL=NOPASSWD: /bin/mount,/bin/umount,/bin/chmod,/bin/chown,/bin/hostname,/bin/mkdir,/bin/rm,/usr/bin/tee,/usr/bin/stat,/bin/cp,/bin/sed,/usr/bin/touch,/sbin/blkid,/usr/bin/lsof,/bin/ls,/sbin/losetup,/sbin/dmsetup,/usr/bin/rsync,/usr/bin/timeout,/usr/bin/getfacl,/usr/bin/setfacl,/tmp/installer_ch_cohesity_linux_agent,/home/cohesityagent/installer,/home/cohesityagent/cohesityagent/data/agent/tmp/installer_ch_cohesity_linux_agent,/bin/systemctl,/home/cohesityagent/cohesityagent/software/crux/bin/cohesity_linux_agent.sh The actual paths for each command may vary in each system. Cohesity keeps adding or removing commands across releases.
Location	Installation directory: `/opt/cohesity` Log file: `/var/log/cohesity`

Install script installer package

The following table explains the action to be performed for installing the script installer package:

In the following commands, replace the Cohesity agent version with the desired agent version.

Action	How to
Download the Agent installer	From the Download Agents window, based on your Linux distribution, select Script Installer and download it to the server you want to protect.
Navigate to the downloaded directory	As the root user with local system privileges on that server, change the directory to the location of the installer package. For SLES 11 SP4, installing the agent as the root user is required.
Make the installer executable	Make the installer executable, for example: `chmod +x cohesity_agent_7.3.2_linux_x64_installer`
Install the Agent	Run the executable: sudo /cohesity_agent_6.6.0d_u2_linux_x64_installer – --install
Location	Installation directory:`/home/<username>/cohesityagent` or `/root/cohesityagent` Log file: `/home/cohesityagent/cohesityagent/logs` You can specify the option `-log-dir <installtion_path>` to specify the directory path where the agent logs will be saved. If this option is not provided, the logs will be saved in the default path

Install Cohesity Agent for Linux PowerPC

To use the Linux PowerPC agent (Java based), Java Runtime Environment (JRE) 8 needs to be installed on the source system.

The following section explains the action to be performed for installing the Linux PowerPC Agent as a ROOT user:

Select Data Protection > Sources.
Click Download Cohesity Agent.
From the Download Agents window, select PowerPC and download it to the server you want to protect.
Change the directory to the location of the installer package and run the following command to install the rpm based installer package for PowerPC distribution:
```
cohesity-java-agent-7.0.1-1.ppc64le.rpm
```
The agent will be installed in the following directory /opt/cohesity and the logs files can be found in /var/log/cohesity.
To uninstall the agent, run the following command:
```
rpm -e cohesity-java-agent
```

For information about all Cohesity Linux agent installer options, see Linux Script Installer Options.

The agent starts after installation completes.

Agent startup behavior following a machine reboot:

CentOS and RedHat (distributions with the "systemd" init system) - The agent starts automatically.
Ubuntu (distributions with the "upstart" init system) - The agent starts automatically.

If a Linux server's /etc/sudoers file is managed by a deployment engine such as Chef, Puppet or others, this could impact Cohesity cluster's interaction with servers that have the Linux agent installed. Take the corresponding actions below:

Agent Installation - User type Action required

As default cohesityagent user

The Cohesity Linux agent is installed using the cohesityagent user by default. For default installations, the cohesityagent is created by the installer. During installation, the installer updates the /etc/sudoers file to allow cohesityagent sudo and no-tty sudo access. Ensure the following settings in the /etc/sudoers file for the cohesityagent user are preserved:

    cohesityagent  ALL=(ALL) NOPASSWD:ALL
    Defaults:cohesityagent !requiretty

An example of the sudoers file is as given below:

#includedir /etc/sudoers.d
dgoble ALL=(ALL) NOPASSWD:ALL
cohbackup ALL=(ALL) NOPASSWD:ALL
Defaults:cohbackup !requiretty

As non default user, example foo

Ensure the above settings in the /etc/sudoers file for the foo user are preserved by replacing the occurrences of cohesityagent with foo.

As root user

No changes required

Install Cohesity Agent for Linux on z/Architecture

To use the Linux on z/Architecture agent (Java-based), Java Runtime Environment (JRE) 8+ (JRE 8, 11, 17) needs to be installed on the source system.

The following section explains the action to be performed for installing the Linux on z/Architecture Agent as a ROOT user:

Select Data Protection > Sources.
Click Download Cohesity Agent.
From the Download Agents window, select s390x and download it to the server you want to protect.
Change the directory to the location of the installer package and run the following command to install the rpm based installer package for z/Architecture distribution:
```
rpm -i cohesity-java-agent-0.0.0-1.s390x.rpm
```
The agent will be installed in the following directory /opt/cohesity and the logs files can be found in /var/log/cohesity.
To uninstall the agent, run the following command:
```
rpm -e cohesity-java-agent
```

Install Cohesity Agent for Linux on on ARM (aarch64)

To use the Linux on on ARM (aarch64) agent (Java-based), Java Runtime Environment (JRE) 8+ (JRE 8, 11, 17) needs to be installed on the source system.

The following section explains the action to be performed for installing the Linux on on ARM (aarch64) Agent as a ROOT user:

Select Data Protection > Sources.
Click Download Cohesity Agent.
From the Download Agents window, select aarch64 and download it to the server you want to protect.
Change the directory to the location of the installer package and run the following command to install the rpm based installer package for z/Architecture distribution:
```
rpm -i cohesity-java-agent-7.3.1-1.aarch64.rpm
```
The agent will be installed in the following directory /opt/cohesity and the logs files can be found in /var/log/cohesity.
To uninstall the agent, run the following command:
```
rpm -e cohesity-java-agent
```

cohesity_linux_agent.sh

The table lists how cohesity_linux_agent.sh interacts with various init systems to issue start/stop/status commands.

If Cohesity does not detect any of the init systems, the installer uses the undetected init system commands.

init system	Commands
systemd	sudo systemctl start cohesity-agent sudo systemctl stop cohesity-agent sudo systemctl status cohesity-agent
upstart	sudo initctl start cohesity-agent sudo initctl stop cohesity-agent sudo initctl status cohesity-agent
SysV	sudo /etc/init.d/cohesity-agent start sudo /etc/init.d/cohesity-agent stop sudo /etc/init.d/cohesity-agent status
undetected	sudo /etc/init.d/cohesity-agent start sudo /etc/init.d/cohesity-agent stop sudo /etc/init.d/cohesity-agent status

Open the following ports on the server:
- TCP port 50051 for backup operations (incoming)
- NFS ports 111 and 2049 for restore operations on a Linux server (outgoing)
- SMB port 445 for restore operations on a Windows server (outgoing)

Register a Physical Server with the Cohesity cluster

Registering a physical server makes its content eligible to be protected or backed up on the Cohesity cluster.

Selecting an Interface Group is not relevant when registering a physical server, despite the option being present on the Physical Server registration page on the Cohesity cluster.

Select Data Protection > Sources.

Click Register > Physical Server.

Specify the hostname (FQDN) or server IP (IPv4 or IPv6) of the server to register. Cohesity recommends using the FQDN.
Click Register.

When registration finishes, a new entry appears in the physical section on the Sources page.

Now you can create a Protection Group with the Registered Source.

You can register a Windows physical server on multiple Cohesity cluster. In a Cohesity cluster failover scenario, when the primary Cohesity cluster goes down, you can use the secondary Cohesity cluster to backup the file/folder on the physical server. However, you cannot register a Windows physical server as an MS SQL server on multiple Cohesity cluster. For more information, Contact Cohesity Support.

Register Veritas Cluster Server (VCS) on Cohesity cluster

To protect VCS, you must first register VCS as a physical server on Cohesity cluster using VCS VIP.

You can register a VCS VIP on multiple Cohesity clusters. For more information, Contact Cohesity Support.

This is an Early Access feature. Contact Cohesity Support to enable the feature.

Red Hat High Availability (Pacemaker) Cluster

To protect the Red Hat High Availability (Pacemaker) Cluster, you must first register it as a physical server on the Cohesity cluster using the VIP address.

Manage Physical Servers

Re-register Cohesity Agent (Windows or Linux)

The re-register functionality on the Cohesity cluster allows you to save the agent settings on the cluster and enables you to perform an agent re-registration with the same settings when required.

With re-registration, the existing file-based protection job would continue to work with the new agent without any intervention. However, the block-based protection job may need to be modified if specific volumes under the job have changed before re-registration.

For block-based protection jobs, the first backup after re-registration will be a full backup.
Re-register functionality is currently supported for Windows and Linux servers.
During agent re-registration, you must use one of these options, Apply settings for the agent preserved on Cohesity UI or Preserve setting during uninstallation of an agent from the server.

Select Data Protection > Sources.
Navigate in the source hierarchy to the Windows or Linux server you want to re-register, mouse over its actions menu, and click Re-register.
Click Apply the Settings for the agent preserved on the <date and time> checkbox if you want to restore the server settings.

If this checkbox is not selected, then the settings saved on the cluster are not applied to the newly registered agent.

During agent uninstallation of a Cohesity Windows or Linux agent, there is an option to preserve settings in the Windows registry or config file for Linux. If you had selected the Preserve Settings option during the uninstall process then deselect the above option during the reregistration workflow.
Click Re-register.

Upgrade Agent on a Physical Server

This option is clickable if an agent upgrade is available for the server. If an agent upgrade is requested while backup jobs or recover tasks are active, the upgrade starts after the jobs and tasks finish.

Navigate to Data Protection > Sources.
Navigate the source hierarchy to the server, mouse over its actions menu and click Upgrade Agent.
Click OK.

Edit Physical Server Registration

Navigate to Data Protection > Sources.
Navigate the source hierarchy to the server, mouse over its actions menu and click Edit.
Edit the desired information.
Click Update Server.

Unregister Physical Server from the Cluster

Navigate to Data Protection > Sources.
Navigate the source hierarchy to the server, mouse over its actions menu and click Unregister.
Click Unregister.

Dataprotect Documentation