Path: csiph.com!news.mixmin.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Anton Shepelev Newsgroups: comp.databases.ms-sqlserver Subject: Re: Make a backup only if necessary Date: Wed, 29 May 2024 00:52:33 +0300 Organization: A noiseless patient Spider Lines: 22 Message-ID: <20240529005233.d0405d2f6f826fd0e8ae0624@gmail.moc> References: <20240527125929.d701039c2aec3196dc3d4731@g{oogle}mail.com> <20240528124112.80ab65ec4a358da57093539b@g{oogle}mail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Injection-Date: Tue, 28 May 2024 23:52:34 +0200 (CEST) Injection-Info: dont-email.me; posting-host="429076323b7d214da263586033ec7617"; logging-data="832233"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/Jty5Dctmz1aHg0WFQNYAVE7/fip7QgfE=" Cancel-Lock: sha1:grU78dHqcXsrte5oxAMISXQ8XUU= X-Newsreader: Sylpheed 3.7.0 (GTK+ 2.24.30; i686-pc-mingw32) Xref: csiph.com comp.databases.ms-sqlserver:2252 Erland Sommarskog to Anton Shepelev: > > I still fail, however, to understand why `first_lsn' > > changes for each subsequent diff. backup. It is > > described as the "log sequence number of the first or > > oldest log record in the backup set." Since the last > > five diff. backups were generated with respect to the > > same full backup, I expected them to have the same > > first_lsn. Why do they not? > > Because the backup itself is logged. Thank you. Now my system uses LSNs to avoid storing redundant differential backups, and I like the result. When I look at a "batch" of my backup files (one full and sequence of differential ones), instead of the typically reguarly spaced files I see only backups taken when the database was in flux, which is great. -- () ascii ribbon campaign -- against html e-mail /\ www.asciiribbon.org -- against proprietary attachments