The 64k limit was due to a tcp/ip stack limitation
I have always found larger buffers (256k) generally provide the best performance. Only if you had lots of small files would I recommend anything less Flashbackup will definitely improve your performance as the data will not need to be uncompressed prior to passed to the backup device. The only factor to consider is that flashbackup will also backup the blocks on the drive which are empty - so you backup the entire volume. I am going to guess you wont see much performance going to disk as you issue is probably not at the backup target as you have a collection of LTO4 drives. A single LTO4 should be able to backup that entire volume in 6 hours easy - even if the SAN is running at 2GB. Can you share any info about your disk config? Is it SAN or internal storage? How many disks are in the config? If you run Windows perfmon how are your disk queues looking? Also - how many split I/O's are you getting? - ensuring proper file system / volume partition can make a decent difference Do you have bad disk fragmentation? All things that can make a difference . . . . ________________________________ From: veritas-bu-boun...@mailman.eng.auburn.edu [mailto:veritas-bu-boun...@mailman.eng.auburn.edu] On Behalf Of Nic Solomons Sent: 16 September 2010 14:44 To: veritas-bu@mailman.eng.auburn.edu Subject: Re: [Veritas-bu] Real World NBU Buffer settings Win2k3 Also worth noting that for 2003+, if you don't have specific RTOs for individual files, you can do volume based backups with your standard licensing (but no individual file restore). http://seer.entsupport.symantec.com/docs/275912.htm Which should give you the same performance boost as flash backup. Make sure you use VSS though - not VSP (why they left the screenshot like that, no idea). Cheers, Nic From: veritas-bu-boun...@mailman.eng.auburn.edu [mailto:veritas-bu-boun...@mailman.eng.auburn.edu] On Behalf Of Martin, Jonathan Sent: 16 September 2010 14:23 To: WEAVER, Simon (external); William Brown; veritas-bu@mailman.eng.auburn.edu Subject: Re: [Veritas-bu] Real World NBU Buffer settings Win2k3 Windows is a piece of cake. Install the client. Select Policy Type: Flashbackup-Windows Setup Selection List: \\.\R <file:///\\.\R> : (change drive letter as required) Run Policy Enjoy monumentally faster backups (on compressed volumes) You cannot backup the system drive (C:) or System State with Flashbackup. I normally run these in a 2nd "OS" policy. Be sure to test a restore. You can do "entire volume" restores, which are just as fast as backups. Or, you can restore individual files. -Jonathan From: veritas-bu-boun...@mailman.eng.auburn.edu [mailto:veritas-bu-boun...@mailman.eng.auburn.edu] On Behalf Of WEAVER, Simon (external) Sent: 15 September 2010 19:00 To: veritas-bu@mailman.eng.auburn.edu Subject: [Veritas-bu] Real World NBU Buffer settings Win2k3 Hi All Anyone got any real world experience on buffer settings: scenarion: Win2k3 San Media, connected to 2GB Fabric attached 8 LTO4 Drives. Due to drive availability, Multiplexing onto one drive. Main problem: One volume (1,7tb in size) takes over 4 days to fully complete. Got the Tuning Guide and Technote 244602, but I tried some settings, only to find the backup would not even mount tape correctly. So back to "no" settings at the mo. Volume are generic files/folders, mixture of large and small sizes. But 1.7TB's in my view should be done quicker. Also Data is compressed. Regards Simon The information contained in this e-mail and its attachments is confidential. It is intended only for the named address(es) and may not be disclosed to anyone else without Attenda's consent.
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