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Re: Backup and bdb-logfile removal
Peter Mogensen wrote:
Hi,
I've been going all documentation I can find (FAQ/bdb-docs..) and I
still have some doubt whether I understand this correctly.
All of your questions are answered in the official BDB docs.
http://www.oracle.com/technology/documentation/berkeley-db/db/ref/transapp/archival.html
These docs are for the current version, 4.6.21, but not much has changed in
the description since 4.2.52.
I run frequent dumps with slapcat to backup the database, but I still
need to cleanup the BDB logfiles and it would also be nice get faster
back online after a crash than you can from LDIF.
So I understand how to create a hot backup by copying the database files
(db_archive -s) and then the log files (db_archive -l) and runing
db_recover -c.
No, "db_recover -c" is for recovering from a catastrophic failure. It's not
for creating a backup.
I can see that I can delete unused log files (db_archive [no options])
from the backup. But when is it safe to remove log files from the active
environment?
db_archive on the active environment lists fewer files than on the
backup (predictable enough).
From the BDB doc page above:
>>
To minimize the archival space needed for log files when doing a hot backup,
run db_archive to identify those log files which are not in use. Log files
which are not in use do not need to be included when creating a hot backup,
and you can discard them or move them aside for use with previous backups
(whichever is appropriate), before beginning the hot backup.
<<
The docs say that running db_archive -d can make recovery impossible.
OK... so I don't do that.
But what is required of my hot backup snapshot to know that I can delete
log files from the active environment? (and which?) and still not
influence the posibility for recovery.
Could anyone list a step-by-step procedure to create a snapshot for
backup and prune the log files from the active environment?
The docs/ref/transapp/archival.html file that SleepyCat bundles in the
BerkeleyDB installation provides all the steps.
btw: openldap 2.3.30/ bdb 4.2.52 (debian) ... but I guess that's not so
important here.
--
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/