Storage read write issues

[nthnu]

Our backups to QNAP NAS have started giving these errors on our jobs. Checking and testing the QNAP using it's tools shows everything normal and no errors anywhere.

[server] to QNAP -- The job failed with the following error: A backup storage read/write error has occurred.

If the storage is tape based, this is usually caused by dirty read/write heads in the tape drive.  Clean the tape drive, and then try the job again.  If the problem persists, try a different tape.  You may also need to check for problems with cables, termination, or other hardware issues.

If the storage is disk based, check that the storage subsystem is functioning properly.  Review any system logs or vendor specific logs associated with the storage to help determine the source of the problem.  You may also want to check any vendor specific documentation for troubleshooting recommendations.

All our jobs go to a deduplication storage folder on the QNAP (via an iSCSI connection). Will reformatting that and starting from scratch help?

Any ideas?

Thanks

[CraigV]

...check below:

https://support.symantec.com/en_US/article.TECH130478.html

Thanks!

[teiva-boy]

Because you're using iSCSI, and something that is not "enterprise-class," (e.g. QNAP) you're going to have to stress test your environment a bit to see if you can re-create the problem.

I'd start with the B2D Test tool, made by Symantec:

https://support.symantec.com/en_US/article.TECH71830.html

Pay attention to the command line option -pdde that runs additional tests to verify deduplication workability.

Note this tool doesn't if passed, say you're supported by Symantec.  Just that, in a best effort, Symantec will help you.  But it's a good first start.

I'd also look into something like iometer and really put the disk subsystem to the test.  I'd do some concurrent rear/write testing using a tool like iometer, and see if you can stress test your iSCSI network, nas, and disks.  

iSCSI when under load can cause issues, and you have to do a lot of troubleshooting to identify where the issues are.  It could be a NIC issue, a driver issue, a switch issue, etc...  This is why fiber channel is more widely used in the Enterprise, over iSCSI.  But when done right, iSCSI over 10GbE can work reasonably well; but takes a lot of tuning to get right.