Hello, I tested changing the block size using these settings with Onstor filers and came up empty. I matched block size changes on the filer with SIZE_DATA_BUFFERS_NDMP. Every test of changing the block size resulted in I/O errors. In the end NDMP performance seems to be highly dependent on the performance of the underlying file system you are backing up along with NDMP throttling to guarantee a certain level of performance for the users accessing the data during the backup. I have also read that you don't have the 64k limit in Windows if you use the VERITAS drivers.
-Dwayne Adams -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Clooney, David Sent: Tuesday, August 21, 2007 6:22 AM To: Martin, Jonathan; [email protected] Subject: Re: [Veritas-bu] NDMP Performance Good idea, >From the unix world myself, however we have overcome the blocksize limit on our windows media servers with Microsoft KB907418. 2003 SP1 I presume Anyhow I think they have now bundled the fix into the next SP release and is therefore not available for download. I have a copy of the fix if you need it. Dave -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Martin, Jonathan Sent: 21 August 2007 13:34 To: [email protected] Subject: Re: [Veritas-bu] NDMP Performance I put in a call to Symantec Tech Support on this, given that its not documented anywhere and the tech indicated this is the write to tape block size. So given that your tape drive can handle it, setting this as high as 256KB can net you performance improvements. I however am on Windows, so 64K seems to be it for me. -Jonathan -----Original Message----- From: Clooney, David [mailto:[EMAIL PROTECTED] Sent: Tuesday, August 21, 2007 4:31 AM To: Len Boyle; Martin, Jonathan; [email protected] Subject: RE: [Veritas-bu] NDMP Performance I was under the impression that if the drives are directly attached there is not a lot that can be done from an NBU point of view. If you are running a 3 way scenario then the touch file could possibly make a difference, I seem to remember from the past that if you are in a 3 way setup you can change the way the NDMP mover agent starts with regard to buffers. Dave -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Len Boyle Sent: 21 August 2007 04:06 To: Martin, Jonathan; [email protected] Subject: Re: [Veritas-bu] NDMP Performance The answer may depend on what device is at the other end of NDMP. I was told that with NetApp NDMP that changing the buffer did not change performance due to the way that the WAFL filesystem handled things. It would be interesting to revisit this and see if they had made any changes to enable larger buffers sizes improve performance. Some of the other NDMP devices with different filesystems may show an improvement. len -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Martin, Jonathan Sent: Monday, August 20, 2007 3:12 PM To: [email protected] Subject: [Veritas-bu] NDMP Performance Anyone know anything about the SIZE_DATA_BUFFERS_NDMP touch file? Is this even still valid? I can't seem to find anything about it in NBU documentation, just a reference in the archives of this mailing list. Is this worth investigating as a performance enhancer for NDMP? -Jonathan _______________________________________________ Veritas-bu maillist - [email protected] http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu _______________________________________________ Veritas-bu maillist - [email protected] http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu Notice to recipient: The information in this internet e-mail and any attachments is confidential and may be privileged. It is intended solely for the addressee. If you are not the intended addressee please notify the sender immediately by telephone. If you are not the intended recipient, any disclosure, copying, distribution or any action taken or omitted to be taken in reliance on it, is prohibited and may be unlawful. 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