Restore error 85 while using other Media server

[Vishnuaabe]

Hi, 

I have an image backed up using Media server A and written to tape now I wanted that to be restored using another Media server B for that I have used Media Host Override option.

But when the restore is running it is failing with error code 85 in the detail status I can get only this information  02/10/2016 01:44:06 - Error bptm (pid=57484) cannot read image from media id E01011, drive index 2, err = 234 02/10/2016 01:44:07 - Error bptm (pid=57484)

The tape device at index 2 has a maximum block size of 524288 bytes, a buffer size of 1048576 cannot be used 02/10/2016 01:44:07 - Info bptm (pid=57484) EXITING with status 85 <----------

after checking this error I have added these parameters SIZE_DATA_BUFFERS, NET_BUFFER_SZ and NUMBER_DATA_BUFFERS to the Media server B using the same values as A, even I am getting the same error.

Any help in this matter?

[Marianne]

There are several discussions in this forum with same issue. The problem is with the hba in server B, not with NBU buffer size. One example : https://www.veritas.com/community/forums/block-size-issue

[Marianne]

See this TN : https://www.veritas.com/support/en_US/article.000017244 You can also use nt_ttu tool (with a tape loaded in the drive) to see what the max block size is on this media server. See this TN: https://www.veritas.com/support/en_US/article.TECH22746

[Vishnuaabe]

Thank how to use the nt_ttu in AIX machine ?

[Marianne · Accepted solution]

Apologies - for some reason I have missed your 'AIX' tag.

I have only ever seen this issue with block size on an HBA with Windows server.
The nt_ttu tool is also Windows only.

No idea how to verify hba block size in AIX.

What I do remember from past experience with AIX is that HBA and/or tape driver must be configured for variable block length. 

You should be able to find more info in NBU Device Config Guide.

[Mark_Solutions]

I wouldnt have thought it would matter as it does look like a HBA issue .. but for a restore you actually use SIZE_DATA_BUFFERS_RESTORE (At least I think this is the case ... as it would actually use whatever the header has written as its block size so have never seen this used !!)

Maybe something in this will be of assistance too: https://mim3dotme.wordpress.com/2013/01/17/change-tuneable-io-hba-settings-on-client-side-aix-for-v7000-and-other-storages-some-useful-planingconfiguration-stuff/

[mph999]

No such thing as SIZE_DATA_BUFFERS_RESTORE ...  (I just double checked by looking in the code - no match)

Once written, the block size cannot be changed when restoring, well not from within NBU.

As Marianne points out ...

"What I do remember from past experience with AIX is that HBA and/or tape driver must be configured for variable block length. "

That's true for all OS, the tape drive must always be able to write in variable length blocks, eg. the headers are different block size than the data blocks for example.

There is no tool I know of in Uix to specify the max block size a drive can write in.  It is easy to work out though, run a backup, if it works, increase the block size and try again, at some point it will fail.