Add and discover Linux hosts

Backup and DR Service discovers file systems, network file share (NFS) shares, and supported databases on Linux hosts. Before you can discover and back up data from these hosts, you must do the following:

Install the Backup and DR agent on the Linux host
Add the Linux host.
Check the iSCSI or NFS connectivity

Add Linux hosts

Use the following instructions to add a Linux host:

In the management console, go to Manage > Hosts.
Select + Add Host.
In the Add Host form, enter the name and an optional friendly name. The name of a host must start with a letter, and can contain letters and digits (0-9). Note that underscore (_) characters are not valid in host names.
Enter the IP address of the host in IP Address and click the plus sign (+) to add it.
In the Appliances section, select the management console managed appliances that you want to serve this host. If the list is long, you can use the Search field to find a specific appliance or group of appliances.
In Host Type, select Generic.
Enter Application Discovery Credentials to discover and protect the database applications on the host. This field is applicable only for MariaDB, MaxDB, MySQL, PostGresSQL, SAP ASE, and SAP IQ databases.
In the Backup and DR agent settings, complete the following steps:
- The Backup and DR agent port is normally port 5106. If it is anything else, enter the port number here.
- You need to supply the secret key generated on Linux host using the instructions in Install the Backup and DR agent on a Linux host or Regenerate the secret key section. You can add the secret key now or later using the Add a secret key instructions but before running the application discovery.
Click Add. If you get a partial success message, use the instructions to Validate backup/recovery appliance to Backup and DR agent connectivity.

Add a secret key

If you want to update the secret key or if you didn't add the secret key initially, you can add it in the Linux host.

Go to the management console, select Manage and then select Hosts.
Right-click the Linux host and choose Edit.
Go to Backup and DR Agent Settings and find the Secret field.
Paste the secret key that you saved earlier in the Secret field and click Save. Ensure the Certificate status changes to Valid. If you get a partial success message, use the instructions to Validate backup/recovery appliance to Backup and DR agent connectivity.

Abnormally long backup jobs and fstrim

Backup and DR Service CBT technology relies on a bitmap that is generated for every write operation on the protected volume. Utilities like fstrim that modify the file system metadata blocks cause the backup process to copy additional data, increasing the backup time.

iSCSI connectivity on a Linux host

If the Backup and DR agent is going to write backup data onto the staging disk using iSCSI, then an iSCSI initiator must be installed on the host.

Install the iSCSI initiator on Linux host

Use the following instructions to install iSCSI initiator on Centos, RHEL, SLES, or Ubuntu hosts.

CentOS

Make sure you have the iscsi-initiator-utils package installed. Use the following command to check the installed package:
```
  yum list installed | grep iscsi
```
You can also use the following command to check the initiator package:
```
  rpm -qa | grep iscsi
```
The output looks similar to the following:
```
  iscsi-initiator-utils-6.2.0.865-6.el5.x86_64.rpm
```
If you see nothing, then you can proceed to install the package with the following command:
```
  yum install iscsi-initiator-utils
```
Validate your iSCSI initiator name with the following command. Each host needs to have a unique initiator name:
```
  cat /etc/iscsi/initiatorname.iscsi
```

RHEL

Make sure you have the iscsi-initiator-utils package installed. Use the following command to check the installed package:
```
  yum list installed | grep iscsi
```
You can also use the following command to check the initiator package:
```
  rpm -qa | grep iscsi
```
The output looks similar to the following:
```
  iscsi-initiator-utils-6.2.0.865-6.el5.x86_64.rpm
```
If you see nothing, then you can proceed to install the package with the following command:
```
  yum install iscsi-initiator-utils
```
Validate your iSCSI initiator name with the following command. Each host needs to have a unique initiator name:
```
  cat /etc/iscsi/initiatorname.iscsi
```

SLES

Make sure you have the iopen-iscsi package installed. Use the following command to check the installed package:
```
  rpm -qa | grep iscsi
```
The output looks similar to the following:
```
  open-iscsi-x.x.x.x
  yast2-iscsi-client-x.x.x.x
```
If you don't see both of these packages, then use the following procedure to install open-iscsi:
1. Run yast2 sw_single
2. In the search, enter iscsi
3. Select open-iscsi and click Accept.
Validate your iSCSI initiator name with the following command. Each host needs to have a unique initiator name:
```
  cat /etc/iscsi/initiatorname.iscsi
```

Ubuntu

Use the following command to install iSCSI initiator on a Ubuntu host:

  sudo apt install open-iscsi

The output looks similar to the following:

  Reading package lists... Done
  Building dependency tree
  Reading state information... Done
  open-iscsi is already the newest version (2.0.874-5ubuntu2.11).
  open-iscsi set to manually installed.
  The following package was automatically installed and is no longer required:
  libnuma1
  Use 'sudo apt autoremove' to remove it.
  0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

View and configure host ports

Ports were set at deployment time in Set up and plan a Backup and DR deployment. Use this section to override the backup/recovery appliance provided port information with new iSCSI port on the host for connecting to the appliance. This port information is sent to the appliances.

Use the following instructions if you want to view or override the port information provided by the appliance:

In the management console, click the Manage drop-down menu and select Hosts.
Right-click a host and click Edit.
Click Add Port.
In the Add port dialog, select the appliance (if multiple appliances connect to the host).
Select WWPN or iSCSI.
Click Add and then Save the host setting.

NFS connectivity on a Linux host

If the Backup and DR agent is going to write backup data onto the staging disk over NFS, then an NFS client must be installed on the host.

Change staging disk format

Use the following instructions to change the staging disk format:

In the management console, click the Manage drop-down menu and select Hosts.
Right-click the host that you want to change the staging disk format and click Edit.
Change the Staging Disk Format to Guest setting from Block to NFS.

This ensures that the staging disk is presented as an NFS share and the Backup and DR agent consumes this share. When you mount an image captured with NFS, it need to be accessed as an NFS share and can't be accessed using iSCSI.

Install the NFS client on a Linux host

Use the following instructions to install NFS client libraries on Centos, RHEL, SLES, or Ubuntu hosts.

CentOS

Make sure you have the nfs-utils package installed. Use the following command to check the installed package:
```
  yum list installed | grep nfs
```
To check the initiator package, run the following command:
```
  rpm -qa | grep nfs
```
The output looks similar to this output:
```
  nfs-utils-lib-1.1.5-9.el6.x86_64
  nfs-utils-1.2.3-54.el6.x86_64
```
If you don't see anything, then you can proceed to install the NFS client package by running the following command:
```
  yum install nfs-utils nfs-utils-lib
```
Make sure rpcbind (portmapper) package is installed on the Linux host with the following command:
```
  yum list installed | grep rpcbind
```
To check the initiator package, run the following command:
```
  rpm -qa | grep rpcbind
```
The output looks similar to the following output:
```
  rpcbind-0.2.0-11.el6.x86_64
```
If you don't see anything, then you can proceed to install the rpcbind with the following command:
```
  yum install rpcbind
```

RHEL

Make sure you have the nfs-utils package installed. Use the following command to check the installed package:
```
  yum list installed | grep nfs
```
To check the initiator package, run the following command:
```
  rpm -qa | grep nfs
```
The output looks similar to the following output:
```
  nfs-utils-lib-1.1.5-9.el6.x86_64
  nfs-utils-1.2.3-54.el6.x86_64
```
If you don't see anything, then you can proceed to install the NFS client package with the following command:
```
  yum install nfs-utils nfs-utils-lib
```
Make sure rpcbind (portmapper) package is installed on the Linux host with the following command:
```
  yum list installed | grep rpcbind
```
To check the initiator package, run the following command:
```
  rpm -qa | grep rpcbind
```
The output looks similar to the following output:
```
  rpcbind-0.2.0-11.el6.x86_64
```
If you don't see anything, then you can proceed to install the rpcbind with the following command:
```
  yum install rpcbind
```

SLES

Make sure you have the nfs-utils-utils package installed. Use the following command to check the installed package:
```
  rpm -qa | grep nfs
```
The output looks similar to the following:
```
  nfs-client-1.2.1-2.6.6
  yast2-nfs-common-2.17.7-1.1.2
  yast2-nfs-client-2.17.12-0.1.81
```
If you don't see either nfs-client or yast2-nfs-xxxx packages, then use either YaST or zypper to install the NFS client packages using the following commands.
- Using YaST, run the following commandL
```
 yast2 --install yast2-nfs-client
 yast2 --install yast2-nfs-common
```
- Using zypper, run the following command:
```
  zypper install nfs-client
```
Make sure rpcbind (portmapper) package is installed on the Linux host using the following command:
```
    rpm -qa | grep rpcbind
```
The output looks similar to the following:
```
rpcbind-0.1.6+git20080930-6.15
```
If you see nothing, then you must install the packages using either YaST or zypper:
- Using YaST, run the following command:
```
  yast2 --install rpcbind
```
- Using zypper, run the following command:
```
  zypper install rpcbind
```

Ubuntu

Use the following command to install NFS client libraries on a Ubuntu host:

  sudo apt install nfs-common

The output looks similar to the following:

  Reading package lists... Done
  Building dependency tree
  Reading state information... Done
  The following package was automatically installed and is no longer required:
  libnuma1
  Use 'sudo apt autoremove' to remove it.

Set the staging disk I/O path (VMware VMs only)

Linux VMware VMs can also select a staging disk I/O path. You can assign either NFS or SAN (iSCSI) transport either using the ESX host, or bypass it and direct it to the VM. NFS transport mode is the default. This has no effect on the Staging Disk Format to Guest setting.

Use the following instructions to configure staging disk I/O path:

In the management console, expand the Manage drop-down menu and select Hosts.

The Hosts page appears.
Filter by hosts of type Generic and for Show only, select Virtual Machines.
Select the host for which you want to configure the staging disk I/O path and click Edit.
In the Edit Host page, go to the Staging Disk I/O Path section.
Select one of the following options using information in this table:

Transport	Backup and DR volumes	Where the volumes are pressented	What they are attached to VM as
NFS transport	Over NFS datastore	ESXi host	VMDK
SAN Transport	Over iSCSI	ESXi host iSCSI initiator	Raw device mapping (RDM)
SAN to Guest	Over iSCSI	Guest VM iSCSI initiator	Block device
NFS to Guest	Over NFS	Guest VM NFS client	NFS share

Click Save.

Find logs and scripts on Linux host

On a Linux host, the agent logs, called UDSAgent.logs, are stored in /var/act/log. You can create scripts to perform pre- and post- actions on applications on the Linux host. To use scripts, create a folder called /act/scripts and store all scripts in it.