Kjell Rilbe wrote:
Working with FB 2.5 on Windows 64 bit, how does nbackup level 0 perform compared to a high-performance copy utility like FastCopy?
I'm asking because my DB is 80+ Gbyte and both the database and the backup are currently on the same physical disk. FastCopy works with large chunks to minimize time wasted on disk seeks.
How does NBackup perform in this regard?
Second question: after transferring the level 0 backup file to a secure backup volume, I want to use it to create a DB copy for test/delev/debug purposes. I can do that using Nbackup restore, b ut does this imply copying the entire database yet again?
With a file copy solution with Nbackup lock, I can essentially use the copy "as is" (need to do Nbackup fixup + sweep though). I.e. a single read+write of 80 Gbyte. Is this possible with a Nbackup level 0 backup approach?
Dmitry Kuzmenko answers:
Ad 1. As I see on my desktop nbackup -b 0 is 2-3 times slower than lock/file copy/unlock. I think this is known behavior.
Ad 2. This is BAD. Because of 2 concurrent operations - read and write. If this is not raid 10, then read+write will be 2 times slower than read from one physical disk and write to another physical disk. This has nothing related to nbackup, it is just about copying any file.
Konstantin Khomoutov adds:
Note that nbackup not only copies the data but also updates a special system table in the database, recording the backup level, timestap and name of the destination file. This is used by nbackup to create backup of the next (lower level). So if you intend to ever take backups of lower levels, I'd say you have to use nbackup to do the job, otherwise lock/copy/unlock is a quite reasonable alternative, I reckon.