Potential Data Integrity problem occurs when the Tivoli Storage Manager Server or Storage Agent uses the Quantum Scalar® i6000 Library

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Abstract

When data is appended to a volume within a Quantum Scalar® i6000 library with an I/O blade and the Tivoli Storage Manager CHECKTAPEPOS option is the default value (YES) or DRIVEONLY, data from the append operation can be lost. No errors are reported unless you try to restore the lost data.

Content

WHO IS AFFECTED:

The problem only affects environments where both of the following apply:

  • The Quantum Scalar® i6000 library is used with an I/O blade and LTO generation 5 or 6 drives.
  • The Tivoli Storage Manager server or storage agent is used with the option CHECKTAPEPOS set to its default value of YES or the DRIVEONLY value.

PROBLEM SUMMARY:

When these conditions are met, the Tivoli Storage Manager server uses a tape drive feature called Data-Safe mode. This feature notifies the server when data is being overwritten and lets the server determine if the overwrite is appropriate. In the case of Quantum Scalar® i6000 libraries, the notification can be deferred such that when the Tivoli Storage Manager server or storage agent is notified of the overwrite condition, the server or storage agent is in the wrong position when it starts appending.

Generally this results in a few data blocks not being written at the start of the append operation. Often this operation leaves a filemark in the middle of the data on the volume, which is an unexpected condition when restoring data from the volume. The following example is of an unexpected filemark in the middle of the data during a restore operation, with the primary identifying values being the "KEY=80, ASC=00, ASCQ=01":

ANR8302E I/O error on drive <drive name> (<drive path>) with volume <volume name> (OP=READ, Error
Number=0, CC=0, rc = 2, KEY= 80, ASC=00, ASCQ= 01,
SENSE=F0.00.80.00.04.00.00.58.00.00.00.00.00.01.30.00.14-
.13.00.00.00.01.57.30.33.30.37.37.4C.09.00.00.60.E4.00.0-
0.00.03.06.00.80.08.40.4C.35.00.12.B6.75.00.00.00.00.00.-
00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00-
.00.00.00.00.00.00.00.00.00.00.00.00.00.32.31.32.30.36.3-
0.38.33.32.30, Description=An undetermined error has
occurred). Refer to the Tivoli Storage Manager
documentation on I/O error code descriptions.

RECOMMENDATION:

Update all Tivoli Storage Manager servers and storage agents that have access to a Quantum Scalar® i6000 library or its drives to use a CHECKTAPEPOS value of TSMONLY. Do not use CHECKTAPEPOS default (YES) or the value DRIVEONLY.

PROBLEM RESOLUTION:

This problem will be resolved in Tivoli Storage Manager server and storage agent versions 6.1.5.300, 6.2.6.0 and 6.3.4.1 with APAR IC92965. When you upgrade to these fixing levels and the conditions are met, any backup attempts that detect this situation fail, therefore preventing any data loss. You will still have to set the CHECKTAPEPOS option value to TSMONLY or OFF if you use a Quantum Scalar® i6000 library.


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Document information


More support for:

Tivoli Storage Manager
Server

Software version:

6.1, 6.2, 6.3, 6.4

Operating system(s):

AIX, HP-UX, Linux, Solaris, Windows

Software edition:

All Editions

Reference #:

1640191

Modified date:

2013-06-24

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