Troubleshooting Veeam Backup Error: “The Device Is Not Ready”

Encountering errors during backup processes can be frustrating, especially when they halt operations and threaten data integrity. One common issue reported by Veeam users is the “The device is not ready. Asynchronous read operation failed” error. This error can appear in both Veeam Agent logs and Veeam Server logs, often indicating a problem with accessing the storage device during backup.

The error messages from the logs typically look like this:

Veeam Agent Log Snippet:

9/7/2019 11:50:39 AM :: Error: The device is not ready. Asynchronous read operation failed
Failed to upload disk. Agent failed to process method {DataTransfer.SyncDisk}. Exception from server: The device is not ready. Asynchronous read operation failed
Unable to retrieve next block transmission command. Number of already processed blocks: [238892].
Failed to download disk.

Veeam Server Log Snippet:

9/7/2019 11:50:39 AM :: Error: The device is not ready. Asynchronous read operation failed
Failed to upload disk. Agent failed to process method {DataTransfer.SyncDisk}. Exception from server: The device is not ready. Asynchronous read operation failed
Unable to retrieve next block transmission command. Number of already processed blocks: [238892].
Failed to download disk.

These logs, while informative, can sometimes leave users wondering about the root cause and how to resolve the issue. Let’s delve into the possible reasons behind this error and explore troubleshooting steps.

One of the initial assumptions when facing disk-related errors is the presence of bad sectors on the storage device. To check for this, running the chkdsk utility is a standard procedure. In the example provided, the user executed chkdsk on the Windows 10 machine running the Veeam Agent:

PS C:WINDOWSsystem32> chkdsk c:
The type of the file system is NTFS.

WARNING! /F parameter not specified.
Running CHKDSK in read-only mode.

Stage 1: Examining basic file system structure ...
2061824 file records processed.
File verification completed.
25656 large file records processed.
0 bad file records processed.

Stage 2: Examining file name linkage ...
10199 reparse records processed.
2649062 index entries processed.
Index verification completed.
0 unindexed files scanned.
0 unindexed files recovered to lost and found.
10199 reparse records processed.

Stage 3: Examining security descriptors ...
Security descriptor verification completed.
293620 data files processed.
CHKDSK is verifying Usn Journal...
41501752 USN bytes processed.
Usn Journal verification completed.

Windows has scanned the file system and found no problems.
No further action is required.

       498828831 KB total disk space.
       458225948 KB in 1527288 files.
         770808 KB in 293621 indexes.
             0 KB in bad sectors.
       2247831 KB in use by the system.
          65536 KB occupied by the log file.
        37584244 KB available on disk.

             4096 bytes in each allocation unit.
     124707207 total allocation units on disk.
       9396061 allocation units available on disk.
PS C:WINDOWSsystem32>

The chkdsk results clearly indicate “Windows has scanned the file system and found no problems. No further action is required.” and crucially, “0 KB in bad sectors.” This eliminates bad sectors as the immediate cause in this scenario. However, the “device is not ready” error persists, suggesting other potential issues.

Possible Causes and Further Troubleshooting:

While chkdsk didn’t find file system errors, the “device is not ready” message points towards a lower-level problem preventing Veeam from accessing the disk. Here are some additional areas to investigate:

1. Disk Connection and Hardware Issues:

   • Loose Connections: Check physical connections if the backup target is an external drive or network storage. Ensure cables are securely plugged in.
   • Failing Hard Drive: Even if chkdsk doesn’t report bad sectors, the drive might be failing in other ways. Monitor drive health using SMART diagnostic tools.
   • Controller Issues: Problems with the disk controller can also lead to access errors. Check device manager for any controller errors.

2. Resource Constraints and Server Load:

   • Server Overload: If the Veeam server or the machine running the agent is under heavy load, it might be unable to allocate resources necessary for the backup process, leading to “failed allocations” and device access issues. Monitor CPU, RAM, and disk I/O usage during backup attempts.
   • “7 Days To Die Server Failed Allocations” Analogy: Although not directly related to game servers, the phrase “server failed allocations” can be conceptually linked. Just like a game server might fail to allocate memory or CPU resources for new players, a backup server or agent could fail to allocate necessary resources to access the disk, especially under stress. This highlights the importance of ensuring sufficient system resources for backup operations.

3. Veeam Agent/Server Configuration and Software Glitches:

   • Agent Issues: Try restarting the Veeam Agent service on the affected machine. In some cases, reinstalling the agent might resolve underlying software glitches.
   • Veeam Server Problems: Restarting the Veeam Backup Server service can also be beneficial. Check Veeam server event logs for any related errors or warnings.
   • Firewall/Antivirus Interference: Temporarily disable firewall or antivirus software to rule out potential interference with Veeam’s communication or disk access. Ensure Veeam processes are whitelisted in security software.

4. Storage Device Specific Issues:

   • NAS/SAN Connectivity: If backing up to network storage (NAS/SAN), verify network connectivity, DNS resolution, and storage device availability. Check NAS/SAN logs for errors.
   • Permissions: Ensure the Veeam service account has sufficient permissions to access the backup target.
   • Storage Device Errors: Check the storage device’s own logs and health status for any hardware or software issues.

Moving Forward:

Troubleshooting “The device is not ready” error requires a systematic approach. Starting with basic checks like physical connections and hardware health, then moving to software and configuration aspects is crucial. While chkdsk is a good first step, it’s often necessary to investigate deeper into system resources, Veeam configurations, and the health of the storage devices involved. By methodically eliminating potential causes, you can effectively pinpoint and resolve the root of the backup failure.