Avamar: Enable NFSv4 Browsing on Linux Client by Configuring avagent.cmd and avtar.cmd

Observed Behavior

The NFSv4 share is successfully mounted on the Linux server, but the Avamar UI does not display any files or directories when browsing the Linux client’s file system.

Verification of NFSv4 mount on the Linux server

Linux administrator confirmed the mount using standard commands.

# Display mounted filesystems
$ df -h
Filesystem            Size  Used Avail Use% Mounted on
devtmpfs               5.8G     0  5.8G   0% /dev
tmpfs                  5.8G     0  5.8G   0% /dev/shm
tmpfs                  5.8G    26M 5.8G   1% /run
tmpfs                  5.8G     0  5.8G   0% /sys/fs/cgroup
/dev/sda2              47G   24G   24G  51% /
/dev/sda5              44G  241M   43G   1% /home
/dev/sda1             950M  228M  723M  24% /boot
tmpfs                 1.2G   12K  1.2G   1% /run/user/42
tmpfs                 1.2G     0  1.2G   0% /run/user/1000
x.x.x.x:/data/col1/orb 70G   48G   22G  69% /mnt/ORBSHARE
tmpfs                 1.2G     0  1.2G   0% /run/user/0

Mount details from </proc/mounts>

# Verify NFSv4 mount entry
$ cat /proc/mounts | grep -i nfs4
x.x.x.x:/data/col1/orb /mnt/ORBSHARE nfs4 rw,relatime,vers=4.0,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=10.xx.xx.xx,local_lock=none,addr=x.x.x.x 0 0

Optional mount statistics (may be unavailable)

# Example output when mountstats is available
$ mountstats
Stats for x.x.x.x:/data/col1/orb mounted on /mnt/ORBSHARE:
  NFS mount options: rw,vers=4.0,rsize=1048576,wsize=1048576,namlen=255,acregmin=3,acregmax=60,acdirmin=30,acdirmax=60,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=10.xx.xx.xx,local_lock=none
  NFS server capabilities: caps=0xffd7,wtmult=512,dtsize=32768,bsize=0,namlen=255
  NFSv4 capability flags: bm0=0xffffffff,bm1=0xfdfffe,bm2=0x0,acl=0x0,pnfs=notconfigured
  NFS security flavor: 1  pseudoflavor: 0
  --- more output omitted ---

Symptom Summary

• NFSv4 share appears in df -h and /proc/mounts as correctly mounted.
• Avamar UI does not list any files or directories under the mounted NFSv4 path when browsing the Linux client.
• Linux administrator confirms that the mount point is functional at the OS level.

Avtar lacks native NFSv4 browsing capability.

The Avamar client (avtar) does not support direct browsing of NFSv4 mount points on Linux servers unless specific command‑line flags are configured. Without these flags, the Avamar UI cannot display the contents of the NFSv4 share, even though the share is correctly mounted on the server.

• The default Avamar client configuration does not include the --forcefs=nfs4 or --browse-nfs options.
• When these options are absent, avtar treats the NFS mount as unsupported and suppresses directory listings.
• This limitation is independent of the NFS server’s export settings or the mount options shown by mountstats (such as vers=4.0, rw, and hard).

Relevant configuration files and locations

Avtar reads command‑line flags from two files located under the Avamar installation’s /var directory. The default paths differ by operating system.
If the files avagent.cmd and avtar.cmd do not contain the required NFSv4 flags, the client cannot browse the mount point.

Missing command‑line flags

# Expected content of avagent.cmd
--browse-nfs --forcefs=nfs4

# Expected content of avtar.cmd
--forcefs=nfs4

The absence of these entries is the direct cause of the inability to view the NFSv4 share in the Avamar UI.

Enable Avamar to browse NFSv4 mount points on Linux clients.

Prerequisites

• Root or sudo access on the Avamar Linux client.
• Avamar client version that supports NFSv4 (such as CentOS 7 client).
• Access to the Avamar UI to verify the mount point after configuration.

Step‑by‑Step Procedure

1. Create the command files if they do not already exist.

# CentOS 7, RHEL, or similar
$ touch /usr/local/avamar/var/avagent.cmd
$ touch /usr/local/avamar/var/avtar.cmd

2. Edit avagent.cmd and add the NFSv4 flag.

# Open the file with a text editor (vi, nano, etc.)
$ vi /usr/local/avamar/var/avagent.cmd
# Insert the following line (press i to enter insert mode in vi)
--browse-nfs --forcefs=nfs4
# Save and exit (Esc, :wq!)

3. Edit avtar.cmd and add the same flag.

$ vi /usr/local/avamar/var/avtar.cmd
# Insert the following line
--forcefs=nfs4
# Save and exit

4. Restart the Avamar client agent to apply the changes.

# Using the service command (compatible with most RHEL‑based systems)
$ service avagent stop
$ service avagent start

# Or a single restart command
$ service avagent restart

5. Refresh the Avamar UI and browse the client file system.

# In the Avamar GUI:
1. Select the affected Linux client.
2. Click “Browse Filesystem”.
3. Navigate to the NFSv4 mount point (e.g., /mnt/ORBSHARE).

Verification

• Confirm that the NFSv4 mount point appears in the Avamar UI file browser.
• Run a test backup or restore of a small file located on the NFSv4 share to ensure that data can be accessed.
• Check the avagent log for any errors related to NFS handling:

$ tail -n 20 /usr/local/avamar/var/log/avagent.log

Additional Tools

• mountstats verifies NFS mount options on the Linux server.
• df -h confirms that the NFS share is mounted.
• Avamar UI for browsing and confirming visibility of the mount point

systemctl status firewalld

iptables -L