JoeHartley3

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July 15th, 2011 09:00

NDMP backup TYPE variable ignored?

I have been working on getting backups of a Celerra written to a virtual tape library on a UNIX machine using NDMP.  According to all the documentation I've read, I should be able to pass an environment variable TYPE to specify the format of the dump.  Further, the Celerra should accept the values of "dump" and "tar".  I know the variable is getting passed, but it seems to always be ignored:

1310745654: NDMP: 4: Session 021 (thread ndmp021) < Backup type: dump >
1310745654: NDMP: 4: Session 021 (thread ndmp021) Name: BASE_DATE Value: 0
1310745654: NDMP: 4: Session 021 (thread ndmp021) Name: FILESYSTEM Value: /jh-cifs
1310745654: NDMP: 4: Session 021 (thread ndmp021) Name: HIST Value: y
1310745654: NDMP: 4: Session 021 (thread ndmp021) Name: TYPE Value: dump
1310745654: NDMP: 4: Session 021 (thread ndmp021) tape service is on a remote side, CALLER_ADDRESS 0x11b94f1.

Note the backup type is dump.

As the backup finishes, this line is shown by server_log:

1310745654: NDMP: 6: Thread nasa00 server_archive: emctar vol 1, 5 files, 0 bytes read, 272731 bytes written

It looks like server_archive is always invoked to use the emctar format, whether I pass dump or tar.  Further, the doc for server_archive says that other formats, including ustar (which is compatible with POSIX-standard tar implementations), are supported.  To me, server_archive looks a *lot* like the pax command, so I'm hoping that I can get an NDMP backup sent from the Celerra in a format other than EMC's own emctar.

Does anyone know if that's possible?

Thanks!

Joe H.

  • Rainer_EMC

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    Posted July 18th, 2011 15:00

    With Celerra NDMP the data format for dump and tar is the same - the difference us mainly how the fs is walked (depth-first vs. breadth-first)

    VBB is very different - it's a block copy like a dd

    Rainer

  • Phukon

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    Posted July 18th, 2011 00:00

    This thread is moved from ECN > Support Forums > General Topics > Discussions

    to ECN > Support Forums > Celerra

  • Peter_EMC

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    Posted July 18th, 2011 02:00

    NDMP does only support three backup types:

    • tar
    • dump
    • vbb

    even if it is using server_archive.

    Please check the NDMP manual for additional informations.

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    Posted July 18th, 2011 12:00

    I understand that the values for TYPE is limited but the data written to my virtual tape device is identical whether I use dump or tar for TYPE.  That was what prompted my original question: Is the value of this variable ignored?  As my magic 8 ball would say, "All signs point to Yes".

    I will give "vbb" a try and see if there's any change to the data.

    Thanks!

    - Joe

  • Rainer_EMC

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    Posted July 19th, 2011 07:00

    Just curious - why do you care about the data format?

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    Posted July 19th, 2011 07:00

    Thanks for this answer, it makes it clear what I can expect for the data that gets written to tape.  Thanks again!

  • Rainer_EMC

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    Posted July 25th, 2011 08:00

    And here the age-old answer:

    The NDMP data format is vendor specific (not specified in the standard) so in general you need the same hardware/software combo to restore

    AFAIK as I know there is one vendor who did write a cross-platform restore – search here on the forum about a discussion on CommVault

    (limited of course – you wont get back Windows owner or ACLs)

    Rainer

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    Posted July 25th, 2011 08:00

    It's the age-old story - questions are being asked about the ability to recover data from a backup image if the original hardware is unavailable.