OA52915: 3490 CHANNEL (PRE-COMPRESSION) BYTES AND DEVICE (POST-COMPRESSION) BYTES BEING REPORTED INCORRECTLY

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• For 3490 architecture devices, the reported channel/host bytes
  (pre-compression) and device bytes (post-compression) written
  may be reported incorrectly in RMM displays causing a
  compression ratio that may appear much larger than it is.  Today
   the channel (host) and the device bytes read or written is
  returned by the device in read buffered log (RBL) and for 3490
  architecture devices, the read and write-byte counters are
  maintained in 3-byte fields (using a 4K scaling factor).   With
  larger logical volumes, for example, 25GB volumes in the IBM
  TS7700 Virtualization Engine, the counters pertaining to the
  channel (host) bytes may overflow (when the number of channel
  bytes read or written reaches around 68GB) and when one of the
  RBL counters overflows, this results in all of the counters in
  RBL being reset to zero.  For 3490 architecture devices, the
  amount of data in the counters, prior to the reset, was not
  saved.   This can result in RMM reporting incorrect data as well
   as incorrect data being reported in the SMF 21 statistics
  record that is cut at demount and includes statistics for the
  mounted volume.    This APAR will address the reporting issues
  in RMM as well as the SMF 21.
  

Local fix

• apply PTF(s)
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  *  Users of the TS7700 Virtualization Engine                   *
  *                 D/T3957.                                     *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  *  Extend support for handling a counter                       *
  *                      overflow in Read Buffered Log (RBL) for *
  *                      3490 tape device type.                  *
  *                                                              *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  

Problem conclusion

• This APAR was developed to extend support for handling a counter
  overflow in Read Buffered Log (RBL) data for 3490 device type.
  For SMF 21 record, the 4-byte fields for channel bytes read and
  written (SMF21BRN and SMF21BWN) will now be used for both 3490
  and 3590 tape device types.  Bit flag SMF21NCT will also be used
  for 3490 devices.  If this bit is ON, it indicates the 4-byte
  fields SMF21BRN and SMF21BWN are valid and should be used
  instead of the equivalent 3-byte fields SMF21BR and SMF21BW.
  Prior to this APAR, the bit flag SMF21NCT and the 4-byte fields
  SMF21BRN and SMF21RWN were only used for 3590 tape devices.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  OA52950 UA98231 UA98269

Modules/Macros

• IGE0001E IECUCBCX IGC0009A IGGSNS02
  

Fix information

• Fixed component name

  DEV SUPPORT TAP

• Fixed component ID

  5695DF110

Applicable component levels

• R220 PSY UA98269

     UP19/02/12 P F902

• R230 PSY UA98231

     UP19/02/12 P F902

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.