VTL - Compression Data Consistency Check / Invalid data signature found

Asset ID:	1-72-1298998.1
Update Date:	2011-10-04
Keywords:

Solution Type Problem Resolution Sure

Solution 1298998.1 : VTL - Compression Data Consistency Check / Invalid data signature found

Applies to:

Sun StorageTek VTL Plus Storage Appliance - Version: 1.0 - Build 1323 to 2.0 - Build 1656 - Release: 1.0 to 2.0
Sun StorageTek VTL Prime System - Version: 1.0 - Build 1813 to 1.1 - Build 2076 [Release: 1.0 to 1.0]
Information in this document applies to any platform.
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***Checked for relevance on 04-08-2011*** (dd-mm-yyyy)

Symptoms

While reading a Virtual Tape (VTape) the following error is seen:
40199 Compression Data Consistency Check : Invalid data signature found on tape [%1] VID

Cause

- The probable cause can be either data integrity signature in compressed blocks does not match the original signature, and/or data received from the storage is corrupted.

The following describes the multiple causes for the reported cases on this issue in detail and troubleshooting steps that helped in resolving it:

1) A hard drive failed in the array at or near the time of the read request
2) There was a momentary data path error that failed to supply the requested read.
3) There is previous data corruption on the VTape usually caused by an unexpected outage to the disk array with Write Cache Mirroring turned off.

Note: This error can come when the HW compression is enabled in VTL software. If there is any additional error message indicating any compression card hardware issue, please refer to the document 1187199.1 for detail troubleshooting.

Solution

In each case an SR needs to be opened to Oracle Support to have the Midrange Disk Support analyze the AllSupportData from the disk array.

Depending on the output from the Disk Support Team follow the actions below:

1) If a failed drive has occurred, then put in a request to have the drive replaced.
2) If no drive has failed, then re-drive the read request from the backup application
3) If the error does not occur again, then cause #2 above applies and no action is necessary.
4) If the error does appear again, then we will need to do a dump of the meta-data and possibly a full tape dump as well to find out if there is indeed data corruption. Please open an support ticket to VTL Support for the Instructions and Utilities.

Note 1: The Get Well Plan was issued to for each respective version of VTL to relieve issues with VTape corruption do to Write Cache Mirroring. It is HIGHLY recommended that all VTL's be upgraded to the Get Well Plan. Please contact VTL Support for patches.

To open a support case, go to the Oracle support website.

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