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Andrei Rînea
Asked: 2011-04-26 09:26:30 +0800 CST

file-system incremental backup - ideally with no downtime for the web site

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I am trying to design a web site with backup in mind. Large media elements would be stored on the file system and a daily backup would be done both for the DB and the file-system (which would hold the media elements).

While backing up the DB seems straight-forward I am curious about backing up the file system. WinRAR allows incremental backup and it's nice and dandy but I wish the site would be fully-usable while the file-system backup is taking place.

What if this (FS) backup takes 10 minutes and a user adds/modifies/deletes a (dozen of) file(s)?

SQL Server 2008 R2 guarantees the consistency of a backup by having a two step process.

  1. Backups all the data up to the backup start point
  2. Backs up the rest of the changes since the start of the backup and it's end

I don't know if something equally awesome could be done to the file system...

backup filesystems web rar data-consistency

4 Answers

  1. What you're describing is CDP:

    http://en.wikipedia.org/wiki/Continuous_data_protection

    Now whether you actually need CDP or not is another matter. Is it really important that you "capture" any file changes that occur while the backup is in progress?

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  2. Best Answer

    Look into filesystems that support snapshots.

    However, for practical purposes, don't worry about it. The cost of solving this problem to solve "someone lost 10 minutes of work" isn't worth your time.

    I'm guessing this is being done with no budget. If not there are a bunch of solutions that would allow you to solve this and still not waste time.

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  3. This company offer backup with no downtime for any Linux/Unix based server. You can check it out, hope it helps.

    http://server-backup.eu/

    They use incremental backups and backup only file changes between two backup cycles.

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  4. I think what you are talkin about is volume Shadow Copy Service It's a feature of windows tha allows you to take a snapshot of the file system while it is in use. The open source project bacular uses this but is complex. I use package called burp and would recomend it. burp supports incremental backup using librsync and therefore is very fast, it will only back up to a linux server so may not be for you.

    The main point is you need to use shadow copy which WinRAR does not support it. I found this script which combines WinRAR and NTbackup, it might work for you.

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