Re: [Bacula-users] confused about Full vrs. Incremental backups pools
On Mon, 25 Sep 2006, Arno Lehmann wrote:
Not exactly true.
Theoretically, you're right of course, but Marks setup uses only Full
and Incre backups.
Nark really should look at using Differentials, even if only from a safety
point of view (any broken incremental in a chain = possibly unrestorable
fileset)
By the way - I do prefer to have longer retention times than strictly
necessary for the given scheme. For example, I'd keep differental
backups for at least 6 weeks - I guess there might be months where you
need 4, not 3, differentials between full backups, and having one
generation more allows not only restores to earlier points in time, but
also ensures I have spare tapes in the pools I can (manually) purge in
case I need them unexpectedly :-)
Ditto. I'm keeping some filesets for 14 months. Archival sets are held
around even longer than that.
WRT spare tapes, once you have a few hundred tapes in the pool it's no
real hardship to keep a stock of 10-20 blank ones in reserve :)
And on the flipside of that - no backup is worth a hill of beans if it
{burns|gets stolen|is washed away|is smashed up} with the computers. A
_good_ data safe (not just a firesafe, they get hot enough inside to melt
plastics) is worth the investment - and that applies whether the data is
stored offsite or onsite.
-
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Re: [Bacula-users] confused about Full vrs. Incremental backups pools
On Mon, 25 Sep 2006, Bill Moran wrote: You need an unbroken chain of incrementals, i.e. from the last full backup to the current date no incremental backup can be pruned. Not exactly true. Differentials can be used to consolidate incrementals. Assuming you make incrementals 6 days a week, and Sunday is for fulls and differentials, set retention on your incrementals to 6 days, differentials to 3 weeks. Then you'll always have enough data to perform an incremental without building a new full. That gives you the standard decreasing granularity with increasing age scheme that most people want. It also gives you a faster way to zero in on a particular file revision. (We routinely get requests to restore XYZ file from ABC date) And it also speeds up full restores (full + last differential + subsequent incrementals) AB - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT business topics through brief surveys -- and earn cash http://www.techsay.com/default.php?page=join.phpp=sourceforgeCID=DEVDEV ___ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
Re: [Bacula-users] confused about Full vrs. Incremental backups pools
In response to Arno Lehmann [EMAIL PROTECTED]: [Problem] Here's the problem...as incremental backups expire and are purged, bacula will often promote the next incremental to a full backup, since it correctly determines that there are no full backups for a particular client in the Incremental pool. Writing a full backup can be disruptive to both the client and backup server, as some backups are over 2TB, with clients on a slow network. I want to avoid unscheduled full backups as a result of promoted incrementals, and I don't want to be doing full backups every 2 weeks to satisfy the retention period of the Incremental pool. Is there anyway to avoid this behavior? Keep the incremental backups for more than a month. You need an unbroken chain of incrementals, i.e. from the last full backup to the current date no incremental backup can be pruned. Not exactly true. Differentials can be used to consolidate incrementals. Assuming you make incrementals 6 days a week, and Sunday is for fulls and differentials, set retention on your incrementals to 6 days, differentials to 3 weeks. Then you'll always have enough data to perform an incremental without building a new full. That gives you the standard decreasing granularity with increasing age scheme that most people want. -- Bill Moran Collaborative Fusion Inc. - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT business topics through brief surveys -- and earn cash http://www.techsay.com/default.php?page=join.phpp=sourceforgeCID=DEVDEV ___ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
Re: [Bacula-users] confused about Full vrs. Incremental backups pools
Hi, On 9/25/2006 8:46 PM, Bill Moran wrote: In response to Arno Lehmann [EMAIL PROTECTED]: [Problem] Here's the problem...as incremental backups expire and are purged, bacula will often promote the next incremental to a full backup, since it correctly determines that there are no full backups for a particular client in the Incremental pool. Writing a full backup can be disruptive to both the client and backup server, as some backups are over 2TB, with clients on a slow network. I want to avoid unscheduled full backups as a result of promoted incrementals, and I don't want to be doing full backups every 2 weeks to satisfy the retention period of the Incremental pool. Is there anyway to avoid this behavior? Keep the incremental backups for more than a month. You need an unbroken chain of incrementals, i.e. from the last full backup to the current date no incremental backup can be pruned. Not exactly true. Theoretically, you're right of course, but Marks setup uses only Full and Incre backups. Differentials can be used to consolidate incrementals. Assuming you make incrementals 6 days a week, and Sunday is for fulls and differentials, set retention on your incrementals to 6 days, differentials to 3 weeks. Then you'll always have enough data to perform an incremental without building a new full. That gives you the standard decreasing granularity with increasing age scheme that most people want. I don't know about most but I at least do, and I usually recommend that to customers, too... By the way - I do prefer to have longer retention times than strictly necessary for the given scheme. For example, I'd keep differental backups for at least 6 weeks - I guess there might be months where you need 4, not 3, differentials between full backups, and having one generation more allows not only restores to earlier points in time, but also ensures I have spare tapes in the pools I can (manually) purge in case I need them unexpectedly :-) Arno -- IT-Service Lehmann[EMAIL PROTECTED] Arno Lehmann http://www.its-lehmann.de - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT business topics through brief surveys -- and earn cash http://www.techsay.com/default.php?page=join.phpp=sourceforgeCID=DEVDEV ___ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
