[gpfsug-discuss] Overwritting migrated files

Lukas Hejtmanek xhejtman at ics.muni.cz
Thu Sep 7 16:07:20 BST 2017


Hello,

we have files about 100GB per file. Many of these files are migrated to tapes.
(GPFS+TSM, tape storage is external pool and dsmmigrate, dsmrecall are in
place).

These files are images from bacula backup system. When bacula wants to reuse
some of images, it needs to truncate the file to 64kB and overwrite it.

Is there a way not to recall whole 100GB from tapes for only to truncate the
file?

I tried to do partial recall:
dsmrecall -D -size=65k Vol03797

after recall processing finished, I tried to truncate the file using:
dd if=/dev/zero of=Vol03797 count=0 bs=64k seek=1

which caused futher recall of the whole file:

$ dsmls Vol03797
IBM Spectrum Protect
Command Line Space Management Client Interface
  Client Version 8, Release 1, Level 2.0 
  Client date/time: 09/07/2017 15:01:59
(c) Copyright by IBM Corporation and other(s) 1990, 2017. All Rights Reserved.

        ActS         ResS         ResB   FSt    FName
107380819676     10485760     31373312   m (p)  Vol03797

and ResB size has been growing to 107380819676.

After dd finished:

dsmls Vol03797
IBM Spectrum Protect
Command Line Space Management Client Interface
  Client Version 8, Release 1, Level 2.0 
  Client date/time: 09/07/2017 15:08:03
(c) Copyright by IBM Corporation and other(s) 1990, 2017. All Rights Reserved.

        ActS         ResS         ResB   FSt    FName
       65536        65536           64   r      Vol03797


Is there another way to truncate the file and drop whole migrated part?

-- 
Lukáš Hejtmánek



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