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IV58584: FILEMONáCOLLATEDáREPORTSáWRONGáBCOUNTáVALUES. APPLIES TO AIX 7100-02

A fix is available

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APAR status

  • Closed as program error.

Error description

  • The?application?is?reading?64KB?from?a?file?in?a?filesyst
    em?occupying?a?
    striped?LV.??????????????????????????????????????????????
    ??????????????
    The?striped?LV?has?a?stripe?width?of?4?disks?(hdisk1,?hdi
    sk2,?hdisk3,???
    hdisk4)?and?a?stripe?size?of?4KB.????????????????????????
    ???????????????
    The?trcrpt?report?shows?that?the?64KB?read?is?generating?
    a?read-ahead???
    sequence,?with?the?first?read-ahead?being?page-ins?for?th
    e?first?8??????
    pages.???????????????????????????????????????????????????
    ???????????????
    trcrpt?reports?that?this?is?processed?a?8?pstarts,?each?f
    or?4KB?each.???
    ?Each?stripe?has?one?pstart?for?each?disk.?There?are?two?
    stripes?read,??
    Thus?there?are?two?pstarts,?total,?for?each?disk.????????
    ???????????????
    ?????????????????????????????????????????????????????????
    ???????????????
    The?detailed?problem?description?is?as?follows(?just?look
    ing?at?the?????
    first?transaction?(index?=?0.00):????????????????????????
    ???????????????
    In?the?filemon?collated?transaction?report,?all?of?the?LV
    M?pend?lines???
    report?32?KB?for?the?bcount,?which?is?the?size?of?the?ent
    ire?read-ahead.
    They?should?be?reporting?4KB?each.???????????????????????
    ???????????????
    The?collated?report?also?provide?a?SCSIDD?iodone?line?wit
    h?its?own??????
    bcount?value.????????????????????????????????????????????
    ???????????????
    There?is?one?of?these?for?each?disk,?each?reporting?8KB?w
    hich?is?correct
    for?the?total?data?sent?to?each?disk?(4KB?for?each?of?the
    ?two?stripes).
    

Local fix

Problem summary

  • The application is reading 64KB from a file in a filesystem
    occupying a striped LV. The striped LV has a stripe width of
    4 disks (hdisk1, hdisk2, hdisk3, hdisk4) and a stripe size
    of 4KB. The trcrpt report shows that the 64KB read is
    generating a read-ahead sequence, with the first read-ahead
    being page-ins for the first 8 pages.
    
    trcrpt reports that this is processed a 8 pstarts, each for
    4KB each. Each stripe has one pstart for each disk. There are
    two stripes read, Thus there are two pstarts, total,
    for each disk.
    
    In the filemon collated transaction report, all of the LVM pend
    lines report 32 KB for the bcount, which is the size of the
    entire read-ahead. They should be reporting 4KB each.
    The collated report also provide a SCSIDD iodone line with
    its own bcount value. There is one of these for each disk,
    each reporting 8KB which is correct for the total data sent to
    each disk (4KB for each of the two stripes).
    

Problem conclusion

  • Modified the code to print proper byte count for LVM pstart
    transactions.
    

Temporary fix

Comments

  • 6100-07 - use AIX APAR IV58735
    6100-08 - use AIX APAR IV58670
    6100-09 - use AIX APAR IV58494
    6100-09 - use AIX APAR IV58494
    6100-09 - use AIX APAR IV58494
    7100-01 - use AIX APAR IV56893
    7100-02 - use AIX APAR IV58584
    7100-03 - use AIX APAR IV58469
    7100-04 - use AIX APAR IV58571
    

APAR Information

  • APAR number

    IV58584

  • Reported component name

    AIX V7.1

  • Reported component ID

    5765H4000

  • Reported release

    710

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Submitted date

    2014-04-02

  • Closed date

    2014-04-02

  • Last modified date

    2016-05-10

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

    IV56893

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

Fix information

  • Fixed component name

    AIX V7.1

  • Fixed component ID

    5765H4000

Applicable component levels

  • R710 PSY U862327

       UP14/08/12 I 1000

PTF to Fileset Mapping



Document information

More support for: AIX Enterprise Edition

Software version: 710

Operating system(s): AIX

Reference #: IV58584

Modified date: 10 May 2016