Troubleshooting issues with malware scanning
(Applicable on scan host RHEL 8.x and NFS version 4.x) When scanning large size backup (~ 200 million files), following error is displayed on the Web UI for failed job:
Failed to get response from NetBackup malware utility.
While scan is in progress on scan host, NFS mount points are not accessible from scan host. Scan job remains in progress and timeout after two days. NFS exports on storage server are accessible.
: Ensure that you use NFS version 3 for mounting IA mounts on scan host over NFS by setting the following configuration in /etc/nfsmount.conf file on scan host:
# grep Defaultvers /etc/nfsmount.conf Defaultvers=3
SSH connection to scan host from media server failed.
: Verify the following scan host credentials:
RSA (SHA256) key
User name
Password
Refer to NetBackup Web UI Administrator's Guide for the scan host configuration.
Error can be due to unsupported scan host.
: For a complete list of supported platforms for the scan host, refer to the Software Compatibility list document.
Not enough space is available on the scan host.
SSH user does not have access to the required directories on the scan host.
On a Windows scan host, check for space availability in
C:\folder.On a Linux scan host, check for space availability in
/tmpfolder.
Media server is not able to fetch the credentials to access scan host from the Primary.
: Check that credentials for scan host are specified.
Default scan operation time out is two days. Time to scan may vary depending on the factors sch as workload type, network bandwidth, backup size.
: Scan time-out is configurable and can be changed by setting the configuration key.
Minimum value: 1 hour
Maximum value: 30 days
Mismatch between nbmalwareutil binary and the ScanManager.
:
Contact NetBackup support.
Malware scanner-specific failure message.
: Refer to nbmalwarescanner logs on the media server for agentless host type pools, or on scan host if it is agent based scan.
This error message appears for one of the following reasons:
IA share is not accessible from the scan host.
: Check IA configuration on storage server. Verify on activity monitor that IA job is successful.
The backup image for which the scan was requested expired after the Instant Access (IA) mount was created. This causes the IA mount to be deleted along with the corresponding NFS export path, resulting in an NFS mount failure on the scan host.
: Ensure that the backup image remains valid for the entire duration of the scan. Avoid initiating scans on images that may expire during the scan process.
Unable to create mount due to the following error in Instant Access:
Failed to fetch image details.
The backup image for which the scan was requested expired before the Instant Access (IA) mount creation. As a result, IA mount creation fails.
: Ensure that malware scans are not triggered for backup images that are close to their expiration time. Verify the image retention period before initiating the scan.
IA share is busy or not accessible.
: Refer to nbmalwarescanner logs on the media server for agentless host type pools, or on scan host if it is agent based scan.
Generic failure during the scan of a backup image.
: Refer to nbmalwarescanner logs on the media server for agentless host type pools, or on scan host if it is agent based scan.
Generic failure during the scan of a backup image.
:
Verify if any scan is in progress.
If no scan is in progress, then obtain the list of such instant access mounts with ID's of the instant access mount created using the GET IA API from the following directory:
/netbackup/recovery/workloads/{workload}/instant-access-mounts
Using the DELETE API, delete the instant access mount:
/netbackup/recovery/workloads/{workload}/instant-access-mounts/{mounId}
Only five backup images can be mounted at the same time on windows scan host.
:
Ensure that scan host is not part of multiple NetBackup domains.
Check if there are any Stale mounts on the scan host by running net use.
Following drive letters are used for mounting the IA shares on the windows scan host. Ensure that they are not in use.
L:\ M:\ N:\ O:\ P:\
Microsoft Windows Defender is not installed on the scan host or not configured properly.
: Ensure that Microsoft Windows Defender is installed on scan host.
Refer NetBackup Web UI Administrator's Guide for the scan host configuration.
Symantec Protection Engine is not installed on the scan host or not configured properly.
: Ensure that Symantec Protection Engine is installed on scan host.
Refer NetBackup Web UI Administrator's Guide for the scan host configuration.
Generic error for Scan failure.
: Contact NetBackup support.
Storage server host name cannot be more than 15 characters for the SMB share support.
If Windows Server 2016 is used to set up Active Directory domain, then it does not allow a connection to a storage server with host name of length more than 15 characters.
: Ensure that the character limit is not more than 15 characters.
Generic failure during scanning backup image.
: Check for the following errors:
Refer to
nbmalwarescannerlogs on the media server for agentless host type pools, or on scan host if it is agent based scan.Check for space on media server storage.
Check for NFS service failure on media server.
Review the nbmalwarescanner to view the infected files list for the backup images in the selected date range.
: Update the date range or recovery files and folders selection to reduce the number of infected files. Retry the operation. You can also perform one of the following:
Select the option which can be used to recover selective clean files.
Skip that backup image from recovery.
There are too many infected files in the selected scan result. If the scan result has infected files greater than 5000, the following message is displayed:
Large number of infected files. To view the complete list of infected files, export the list.
: Export the infected file list in
.csvformat and download it to view it.There are many infected files in the selected scan result or the infected file paths are long to be captured in the database. Following error message is displayed:
Large number of infected files.
: This result cannot be exported or viewed.
: As the results cannot be exported or viewed, review the scan logs to view a detailed list of the infected files for the selected scan result.
For large size backup, scan operation is divided into parts. For example, if total number of files in the backup are 1,000,000, the scan operation will be divided into two parts of 500,000 files each.
Each part would be created and scanned separately. Each part can be assigned with different scan host. The Malware detection UI displays only single entry for backup.
: Each divided part details can be obtained by using the REST API.
When performing a malware scan operation with the NetBackup Malware Scanner installed on the scan host, it fails with the following error message:
Missing environment variable NB_MALWARE_SCANNER_PATH
: Ensure that NetBackup Malware Scanner is installed. Note the install location.
Login on the scan host as user using the same user credentials that were provided during scan host configuration on the primary server. Add the following lines to ~/.bashrc:
export NB_MALWARE_SCANNER_PATH=<installLocation>/savapi-sdk-linux64/bin
export PATH=$PATH:$NB_MALWARE_SCANNER_PATH
Malware scanning on Windows scan host may fail if there are cygwin mks toolkit installed.
: UNIX utilities are installed, however, defined scanuser cannot have those UNIX utilities in the PATH variable.
Error/Issue | Description | Workaround |
|---|---|---|
|
|
|
When upgrading NetBackup from previous version to NetBackup version 10.3 or later with the following options selected, the
No images match the search criteriamessage is displayed:Options
Fields
: Backup images
: NAS-Data-Protection
: Copy2
: Not scanned (Default)
: Assets by policy type
: NAS-Data-Protection
: Copy2
: Select the required scanner host pool.
: Not scanned (Default)
Workaround
To view the images that are backed up, ensure that you select the option as to scan the NAS-Data-Protection backup images created on earlier version of NetBackup media server.
File write error
File write error
While running a malware scan on NAS-Data Protection Policy, a
.tar.gzfile (~13 GB) was skipped with the following error message:File write error
The NetBackup Malware Scanner, also known as Avira, extracts the contents of compressed or archived files to a staging volume prior to scanning. If there is insufficient space in the staging volume to extract the compressed or archived files, those files may be skipped during the scanning process and will be reported as unscannable files. It is possible to export a list of unscannable files from the scan results. The reason for skipping a file will be indicated as follows:
File write error
Workaround:
The default size of the staging volume is 10GB, which must be increased if there is a large number of compressed or archived files in the backup, or if the compressed or archived files are nested, such as a zip file containing
.jaror.warfiles.Note:
In such instances, the user can resize the staging volume using the Flex Console. The maximum size for the staging volume is 50GB.
When using Instant Access mount points for malware scan (traditional malware scan) in NetBackup versions prior to 10.3, performance issues were observed.
Workaround: Upgrade to NetBackup media and storage server 10.3 or later. NetBackup 10.3 introduces the feature. This improves the instant access time as well as the scan performance.
The following table provides the differences between the traditional malware scan and dynamic scan:
Key scanning procedure | Traditional malware scan using Instant Access mount points | Dynamic scan |
|---|---|---|
Instant access stage. | Analyzes the tar stream and builds each file's header and extent map file (LMDB database), which is time consuming for large number of files in the backup. | Restores TIR (catalog database) and IM (image metadata) information from fragment. |
Instant access share (NFS/SMB) is mounted and user tries to list or access the file. | Accesses it's header file and reads the attribute from it. | Query's the directory from catalog database to get all the files and directories which are under this directory. It can also query each files and directories attribute to the output. |
Scan host opens a file | Opens and loads the LMDB database. | Builds the index in memory and reads directly from data container.
|
Scan host reads a file | Searches from LMDB database and reads from data container. | If storage server is 3rd party storage vendor, it reads data through OST interface directly. If storage server is PureDisk, it searches from mapping table and reads data from data container. |
The following table provides the details for the respective log files to be viewed depending on the use case:
Table: Log file locations for Agentless scan host
Use case | Components on primary server | Components on media server | Log file path |
|---|---|---|---|
Configurations | nbwebservice | ncfnbcs | For primary server:
For media server:
|
Scan process | nbwebservice bprd | ncfnbcs nbmalwarescanner | |
Recovery | nbwebservice bprd |
Table: Log file locations for NetBackup client as the scan host
Use case | Components on primary server | Components on the scan host client | Log file path |
|---|---|---|---|
Configurations | nbwebservice | nbsubscriber |
|
Scan process | nbwebservice bprd | nbsubscriber | |
Recovery | nbwebservice bprd |
For VMWare VM backup scan, ensure that you use scan user with uid=0. SSH login is disabled by default and user may not enable it for security reasons.
Workaround
In above scenario, perform the following:
If SSH login is disabled for the root user, then non-root scan user can be added to group 0 (root) to be able to scan all the files.
For example, uid=1001(scanuser) gid=1001(scanuser) groups=1001(scanuser),0(root)
During upgrade, the malware status for Hyper-V images created in NetBackup version prior to 11.0.0.1 are displayed as . For newly backed up images post upgrade, default malware status for Hyper-V backup images will be displayed as .
Workaround
User can perform malware scan on the Hyper-V images displayed as .
When using Instant Access mount points for malware scan (traditional malware scan) for VMware backup images in NetBackup versions prior to 11.1, performance issues were observed.
Workaround
Upgrade to NetBackup primary, media and storage server 11.1 or later. NetBackup 11.1 introduces the VxMS based Instant access feature for malware scanning of VMware backup images which is based on the dynamic scan feature. This improves the instant access time and scan performance.
Note:
For more information on dynamic scan which was applicable for non-VMware workload, refer to Issues in scan performance section. VxMS based Instant Access is applicable for VMware backup images if it's backup policy has option enabled, that is, VxMS enabled backup, else it will continue using the traditional Instant Access method.
The following table provides the differences between the traditional malware scan and VxMS based Instant Access scan:
Traditional malware scan | VxMS based Instant Access scan |
|---|---|
To provide IA mount point for traditional malware scan for VMware backup image, it uses third party open source tool called . | VxMS-based intelligent automation eliminates the need for any external tools for malware scanning. It relies on the VxMS catalog and records to retrieve files from the backup image. |
Adding an extra layer of extends IO durations and hinders malware scanning efficiency. | VxMS offers a solution by utilizing VxMS-based records from the backup image, which allows for quicker execution of file operations. |
The ability to scan malware in batches is unavailable. | The VxMS-based IA scans extensive VMware backups in batches of 500,000 files, with each batch being handled by a different scan thread. |
After upgrading NetBackup Flex Scale from version 3.5 to later version, the NFS mount daemon (nfs-mountd) may not initialize correctly. As a result, malware scan operations fail with the following error message because the required Instant Access (IA) NFS mounts are unavailable on the scan host:
systemctl status nfs-mountd * nfs-mountd.service - NFS Mount Daemon Loaded: loaded (/usr/lib/systemd/system/nfs-mountd.service; static; vendor preset: disabled) Drop-In: /etc/systemd/system/nfs-mountd.service.d `-override.conf Active: active (running) since Wed 2025-11-26 20:17:14 IST; 17h ago Main PID: 766 (rpc.mountd) Nov 26 20:17:15 systemd[1]: /etc/systemd/system/nfs-mountd.service.d/override.conf:2: Failed to add dependency on rpcb> Nov 26 20:17:16 systemd[1]: /etc/systemd/system/nfs-mountd.service.d/override.conf:2: Failed to add dependency on rpcb> Nov 26 20:17:18 systemd[1]: /etc/systemd/system/nfs-mountd.service.d/override.conf:2: Failed to add dependency on rpcb> Nov 26 20:19:31 systemd[1]: /etc/systemd/system/nfs-mountd.service.d/override.conf:2: Failed to add dependency on rpcb>
This issue occurs due to a service startup dependency timing issue between the following system services:
rpcbindnfs-mountd
After the NetBackup Flex Scale upgrade, the nfs-mountd service may start before the rpcbind service is fully initialized, which results in improper NFS service initialization. This prevents NetBackup from successfully creating or accessing Instant Access NFS exports required for malware scanning.
Workaround:
Perform the following to reinitialize the NFS services:
- Disable NFS version 3 server services :
setting NFS disable-nfsv3
- Enable NFS version 3 server services:
setting NFS enable-nfsv3
The nfs-mountd service initializes successfully without rpcbind dependency errors.
Instant Access NFS mounts are created and accessible from the scan host. Malware scan operations complete successfully without failures.