Re: Message

[Neil Palmer <neilp@xxxxxxxxxxx>]

This is from an old V3R2 APAR.  On newer releases, check out the STRDSKRGZ
command.:


Users who create large numbers of Byte Stream Files (Bsf's:  all
  OS/400 object type *STMF and some *DOC objects) may experience
  DASD fragmentation problems on their AS/400 systems, depending
  on the number of files created, the nature of change to those
  files, and the file sizes.

  "DASD fragmentation" occurs when only small, scattered pieces of
  disk storage remain available for new usage, even though overall
  DASD utilization may not be approaching 100%.  Although AS/400
  storage management can combine smaller pieces to appear like
  larger ones up to a point, DASD fragmentation can have a
  significant impact on system performance; beyond this, a totally
  fragmented system will not IPL.  A CPI0999 message is issued to
  the QSYSOPR message queue when system fragmentation reaches a
  point of significant concern.  In general, action should be
  taken when this message is received to reduce fragmentation that
  has already occurred.  An IPL de-fragmentation utility is
  available for this purpose; see Licensed Internal Code PTF
  MF12857 for more information regarding the de-fragmentation
  utility.  In addition, this PTF is recommended for all users of
  Bsf's to reduce the likelihood of DASD fragmentation occurring
  due to Bsf usage.  Those considering this PTF should read this
  cover letter in its entirety and understand the changes being
  introduced prior to applying the PTF.

  Byte Stream Files associated with this change can be created in
  the following means:

    o QDLS          - Some Document Library Objects (DLO's)
                      also have an associated Bsf (object type
                      *DOC).  For instance, each DLO accessed
                      from a PC via Client Access/400 has an
                      associated Bsf.

    o Client Access/400 and
      File Serving  - PC files are stored as Bsf's on AS/400
                      server systems.  Objects in Shared folders
                      are stored as Bsf's on the AS/400.

    o UNIX-like APIs- Application Program Interfaces exist that
                      create Bsf's as *STMF objects.

    o Optical       - The Optical file system uses Bsf's.

    o LAN Server/400- Each Network Server Storage Space uses two
                      Bsf's.  This is not expected to be of any
                      significant impact to the fragmentation
                      problem, except for users who create and
                      destroy Network Server Storage Spaces
                      repeatedly and often.

  ----------------------------------------------------------------

  The number of bytes of storage for each *STMF Byte Stream File


  can be determined as follows:

  1) Enter the Work with Object Links (WRKLNK) command on an
  AS/400 command line, identifying the path to the Bsf of interest

  2) Select option 8, "Display Attributes" next to the Bsf

  3) Page down to the second panel of attributes

  4) The "Allocated Size of Object" value provides the number of
  bytes associated with the Bsf

  ----------------------------------------------------------------

  This PTF introduces changes to how storage is managed for Byte
  Stream Files being created, enlarged and truncated.  In general,
  additional storage may be used for each Bsf.  Managing the
  storage in large blocks reduces DASD fragmentation.

  For storage-constrained systems, these changes may have the
  following net impacts:

    o Users with many small Bsf's may be affected by a
      minimum size change from 1024 to 2048 bytes.
    o Each Bsf less than 32,768 bytes in size could be roughly
      500 bytes to 16,000 bytes larger than prior to this PTF,
      depending on Bsf size.
    o Each Bsf between 32,768 bytes and 525,000 bytes in size
      could be up to 36,864 bytes larger than before this PTF,
      depending on Bsf size.
    o Each Bsf between 525,000 bytes and 2 gigabytes in size
      could be up to 103,768 bytes larger than before this PTF,
      depending on Bsf size.

  For those with need of specific details, the following changes
  will occur:

  1) New Bsf's will be created with a minimum size of 2048.  The
  minimum size was previously 1024 bytes for an empty file and
  1536 bytes for a file containing less than 512 bytes of data.

  2) All new Bsf sizes will be in 32,768-byte increments, except
  for Bsf's less than 32,768 bytes in size.  These small Bsf's can
  be 2048, 4096, 8192 or 16,384 bytes in size.  Bsf's created
  prior to this PTF being applied will be modified only as they
  are changed by the user, copied, or saved and restored.
  Previously, all sizes were rounded to 512-byte boundaries, which
  minimized storage consumption, but maximized fragmentation.

  3) Small additional amounts of storage will be added on larger
  Bsf's.  For Bsf's between 65,000 and 525,000 bytes in size, this
  will be no more than 4096 bytes.  For larger Bsf's, this
  difference will be no more than 71,000 bytes.

...Neil





"Dave Snyder" <dsnyder@blcnet.com>
Sent by: midrange-l-admin@midrange.com
2002-02-04 15:26
Please respond to midrange-l


        To:     midrange-l@midrange.com
        cc:
        Subject:        Message


Can someone explain this message, how critical is it, what causes it, and
how can I avoid it in the future?
Thanks.
Dave

 Message ID . . . . . . :   CPI0999       Severity . . . . . . . :   80
 Message type . . . . . :   Information
 Date sent  . . . . . . :   02/04/02      Time sent  . . . . . . :
14:43:49

 Message . . . . :   Storage directory threshold reached.
 Cause . . . . . :   The storage directory is nearing capacity.  This is a
   potentially serious system condition.  This message will be repeated
until
   an IPL has been performed.
 Recovery  . . . :   The amount of storage used on the system must be
reduced.
   To reduce the amount of storaged used, do the following:
     -- Delete objects from the system that are not needed.
     -- Save objects that are not needed online by specifying STG(*FREE)
on the
   Save Object (SAVOBJ) command.