In general, your backup software should handle making incremental dumps, even from a split mirror. What are you using to write data to tape? Are you simply dumping the whole file system, rather than using standard backup software?
ZFS snapshots use a pure copy-on-write model. If you have a block containing some data, and you write exactly the same data to that block, ZFS will allocate a new block for it. (It would be possible to change this, but I can't think of many environments where detecting duplicate blocks would be advantageous, since most synchronization tools won't copy duplicate blocks.) rsync does actually detect unchanged portions of files and avoids copying them. However, I'm not sure if it also avoids *rewriting* them, so it may not help you. You also wrote: >RMAN can [collect changes at the block level from Oracle files], yet that >still keeps things >down at a DBA level, yet I need to keep this backup processing at the SA level. This sounds like you have a political problem that really should be fixed. Splitting a mirror is not sufficient to have an Oracle backup from which you can safely restore, so the DBAs must already be cooperating with the SAs on backups. Proper use of the database backup tools can make the backup window shorter and zfs send/receive can be used to back up only changed blocks; vxfs also has incremental block-based backup available, but the licensing fees may be high. This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
