Disk errors from "false XOR diagnostic test failures"?

Hi,

The issue you're describing—Media Errors and Predictive Failure alerts on Dell R740 disks—could indeed be related to "false XOR diagnostic test failures," as mentioned in the Dell support article. Here's how you can effectively verify and address this:

Steps to Verify "False XOR Diagnostic Test Failures"
Check Firmware Versions:

The Dell support article likely references a firmware update that addresses false XOR diagnostic test failures. Ensure that the firmware on your disks (and the PERC controller) is up to date.
You can verify the current firmware version of your disks using the MegaCLI or perccli utility (for PERC controllers). For example:
bash
perccli /c0 /eall /sall show all | grep "Firmware"
Review Disk Logs:

Use the perccli or MegaCLI tool to check the disk logs for XOR-related errors. For example:
bash
perccli /c0 /eall /sall show error
Look for entries mentioning "XOR" or "diagnostic test failures."
Run Extended Diagnostics:

Perform an extended diagnostic test on the affected disks using the PERC controller. This can help confirm whether the errors are persistent or false positives. For example:
bash
perccli /c0 /eall /sall start patrolread
Monitor the results for any XOR-related failures.
Compare with SMART Data:

Use smartctl (from the smartmontools package) to check the SMART attributes of the disks:
bash
smartctl -a /dev/sdX
Focus on attributes like:
Media_Error_Rate
Other_Error_Rate
Predictive_Failure_Count
If these values are high but the disks otherwise function normally, it could indicate false positives.
Check Dell Support for Specifics:

The article you linked (https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=700gg) may provide additional details about the issue. Look for:
Known firmware versions affected by the bug.
Steps to mitigate the issue (e.g., updating firmware or disabling certain diagnostics).
Test Disks in Another System:

If possible, move the suspect disks to another server or test environment to see if the errors persist. This can help rule out environmental or controller-specific issues.
Monitor Disk Performance:

If the disks are still in use, monitor their performance for I/O errors or latency spikes. Tools like iostat or dmesg can help:
bash
iostat -x 1
dmesg | grep -i error
Next Steps
If the errors are confirmed as false positives due to XOR diagnostic test failures, updating the firmware (as per Dell's recommendation) should resolve the issue.
If the errors persist after firmware updates, the disks may indeed be failing and should be replaced.