Hello, All!
We use NBACKUP for physical replication of the databases. For that we added 2
features:
1) We only read one sector (with header) of each page when scanning for
changes. This is helpful for
SSD media and might provide 4x-32x speed up.
This is probably not important for FB3, as it will have SCN pages, but is very
useful optimization
for 2.X ODS.
2) We added option into NBACKUP utility to create change set based on baseline
GUID rather than level.
-B <level>|<GUID> <database> [<filename>] Create incremental backup
This is the same GUID that is displayed in GSTAT output:
Database backup GUID: {35F5915A-4A62-4A27-AD91-6FB0EBDCCF11}
To update offline copy of the database over WAN we use the following procedure
in a shall script:
- obtain baseline GUID of the database using GSTAT -h
- pull changes using SSH+NBACKUP using baseline GUID
- if pull is successful apply changes to a local copy
- if incremental pull fails get clean copy of the database using "NBACKUP -B
0", CAT and DD (we have
implemented download resume in a shall script)
Pull might fail if baseline with given GUID doesn't exist in the database (it
was restored from gbak
backup, etc).
This idea of using nbackup for exact this purpose was in the original design,
data formats, etc
although it was never completed. Changes do not affect engine code.
If there are no objections to this design I will ask Dmitry Starodubov to port
this code to FB3 and
submit a patch for integration.
Thanks,
Nikolay Samofatov
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