> Is there a way to perform incremental backups using in-file > delta technology (backup only changes within a file)? I've seen a lot of > features/options for Netbackup but I have never seen this...If indeed there > isn't ...why isn't this type of ESSENTIAL technology part of > Netbackup?
As others have said this is what all deduplication products do, at least for any file larger than their minimum. Most have a window size of a certain number of blocks that they look at, calculate a hash value, and then see if they already have that hash stored in their tracking database - if they do then they just replace the data with a pointer to the blocks already stored. There's a lot more detail, and it is the detail that differentiates the various solutions out in the market. Files below a certain size are just backed up anyhow as it takes longer to do the sums than it is worth. To say NetBackup doesn't do this isn't quite accurate. It supports lots of different VTLs and now several OpenStorage products that include deduplication, so at the point where the backup is stored you can get your savings - for example your virtual machine backups I'm sure would deduplicate very well. What that doesn't save you is actually reading the backup off the disks and sending it all the way to the backup storage device. If you use NetBackup PureDisk Deduplication Option (PDDO), the deduplication happens at the NetBackup Media Server. That Media Server could be 'close' to the clients - in Solaris it could be the global zone of a zoned server. I'm not sure if the Media Server is yet supported in a VM; the Master is now, and I can't see any technical reason why for a network-attached storage unit like PDDO it couldn't be supported from a VM (asides from needing to resource the VM enough) - so you might be able to have the Media Server in the same physical server as the backed-up VMs. If you use Symantec PureDisk the deduplication happens in the client (i.e. your VM) but PureDisk is not NetBackup. EMC Avamar is also in-client deduplication. William D L Brown ----------------------------------------------------------- This e-mail was sent by GlaxoSmithKline Services Unlimited (registered in England and Wales No. 1047315), which is a member of the GlaxoSmithKline group of companies. The registered address of GlaxoSmithKline Services Unlimited is 980 Great West Road, Brentford, Middlesex TW8 9GS. ----------------------------------------------------------- _______________________________________________ Veritas-bu maillist - Veritas-bu@mailman.eng.auburn.edu http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu