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Windows 2012 R2 - NUMBER_DATA_BUFFERS not being used

Kelly_Stevenson
Level 4

NB 7.7.1

I have a RedHat master - with lto6 tape drives and a few Windows 2012 R2 media servers.

The NUMBER_DATA_BUFFERS and SIZE_DATA_BUFFERS - are set on the Red Hat master - /usr/openv/netbackup/db/config - and work great.

However - when we set the same values on the Windows 2012 R2 media servers - it will not use the values we specify - using same values as the RedHat master.

It keeps using the default 65536 and 12 values.

They are located in C:\program files\veritas\netbackup\db\config

NUMBER_DATA_BUFFERS

SIZE_DATA_BUFFERS

 

Did something change in NB 7.7.1 to adjust buffers in Windows media servers? The tuning guide still hasn't been updated for 7.7.

 

Regards

 

Kelly

 

 

7 REPLIES 7

sdo
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Are you sure that the files do not have a ".txt" file name extension?

What does a DOS/cmd/CLI     dir <path>       command show?

Nicolai
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Agree with SDO - check file extension. Windows Explorer per default hide known extension. Go into Folder Option -> View and uncheck "Hide extension for known file types".

The two file must be named excatly NUMER_DATA_BUFFERS and SIZE_DATA_BUFFERS.

The bullet proof way to do it :

  • go to C:\program files\veritas\netbackup\db\config
  • open a command promt
  • type the follow commands
  • echo 262144 >  SIZE_DATA_BUFFERS
  • echo 512 > NUMBER_DATA_BUFFERS

Done - you now have to files without extension

Mark_Solutions
Level 6
Partner Accredited Certified

If your media servers are reusing tapes which have previosuly been used and so already have the default 64k block size then they do not get changed.

To get the servers to use the new block size you will need to relabel the tapes before they are reused (making sire they have no vaildi data on them of course!)

Just select the tapes in the library, right click and select "label", choose a media server and de-select the "verify" option .. this forces the header to be overwritten and will use the new block size.

The NUMBER should change however so if this is not honored the most likely issue is that it has the .txt extentiosn as mentioned earlier ... all assuming of course that you have NetBackup installed to C\Program Files\Veritas on the media servers...

Nicolai
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Relabel is not needed for  tapes with variables block size (LTO/STK/IBM tape drives). The block size is a per image setting in Netbackup

 

Mark_Solutions
Level 6
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Nicolai ... by block size i mean as it writes chunks to tape .. which NetBackup calls buffer size

I have found that if you use a tape with the default buffer size (64k) it writes that to the tape header.

If you then change your buffer size to 256k the tape, even when reused after expiry, does not take on the new buffer size as it reads the header first and sets the block size to what the tape is using.

A relabel forces the tape to take on the new buffer size

Nicolai
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We are talking SIZE_DATA_BUFFERS usally 262144 (256K) right ?

I have never experianced what you have seen, but I am also on UNIX. There may be a diffrence.

According to Martins post the, SIZE_DATA_BUFFERS value is written to to Image header, and not media header. Therfor it should not be needed to re-label a media, as this will re-write the media header.

https://www.veritas.com/community/forums/pci-requirement-show-encryption-get-plan#comment-10787401

 

 

 

Mark_Solutions
Level 6
Partner Accredited Certified

I do wonder if there are version differences here .. and also if the scratch pool is used

If a scratch pool is used i get the feeling the header is always overwritten as the tape could go into various volume pools etc ...but i haven't had the opportuninty to test that.