From: <swp...@sn...> - 2006-08-04 07:50:20
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flexbackup-at-worreby.ch |Lists| wrote: > 1. Have you the slightest idea how it's done in the reality? > That's standard procedure to restore full backup plus all=20 > incrementals you have, if you invented some other schema, > please let me know=20 > (at work we're currently backing up between 15-20 TB / night) and > 2. What's worse? Dataloss or too much data!!! Let us first agree that data loss is totally unacceptable. I'm not arguing that data loss is a good thing. (Am i? Where?) But for me, "too much data" is *ALSO* unacceptable, because it does not=20 represent reality. Let me illustrate with a scenario: * I start with a directory e.g. under Apache's configuration that has a single file a.conf * I make a full backup. * rm a.conf * Add a file b.conf * (Notice that at no point in time was there ever more than one file in the directory) * I make an incremental backup. * Hard disk crash * Restore full backup * Restore incremental backup Result with current flexbackup: A directory containing both a.conf AND b.conf. Wouldn't you rather end up with a directory containing *exactly* b.conf=20 - the exact contents of the directory when the incremental backup was mad= e? Ok, so in a directory where there is supposed to be 1 single file you=20 may be able to remember yourself to delete a.conf (because it is *not*=20 supposed to be there). Lets just hope I slept well and didn't remove=20 b.conf instead by accident because I was tired... ;) But with "between 15-20 TB" of data as you put it? Who can remember=20 which of the gazillion files to delete? No, I don't want that to be a guessing game. In some (most?) cases, "too much data" is just annoying - not really=20 catastrophic. But in some cases (e.g. conf.d, cron.d, *.d directories,=20 or a file containing sensitive data that was deleted) this *is*=20 catastrophic. I could end up with a system that won't boot or misbehaves=20 or is dangerous after a full+incremental restore. I will not trust my system+data to such a backup-system. Are *you*=20 comfortable with that? What is the down side of being able to restore=20 reliably? You are right, I don't know "EMC Networker, Veritas Netbackup, HP Data=20 Protector", but I'm willing to bet they can restore a directory=20 containing *exactly* b.conf. (Am I right?) Peter --=20 Peter Valdemar M=F8rch http://www.morch.com |