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File system fragmentation - berkeley-db

This is a discussion on File system fragmentation - berkeley-db ; I tested this again after a couple of years, and the behavior doesn't seem to have changed: If a Berkeley DB database is written using TDS with a reasonably sized cache, data is written from the cache to the file ...


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  #1  
Old 07-16-2008, 03:40 PM
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Default File system fragmentation

I tested this again after a couple of years, and the behavior doesn't
seem to have changed: If a Berkeley DB database is written using TDS
with a reasonably sized cache, data is written from the cache to the
file system in what a appears to be a random fashion. Apparently, a lot
of holes are created, which are then filled. This degrades file system
performance and makes hot backups somewhat difficult (because the read
performance is a fraction of that what can actually achieved).

Is there still no way to preallocate the contents of B-tree files?

(Without TDS, the problem disappears, it seems to be related TDS or the
cache size.)
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  #2  
Old 07-21-2008, 12:36 AM
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Default Re: File system fragmentation

post to http://forums.oracle.com/forums/forum.jspa?forumID=271
they have bdb dev taking questions
On Jul 16, 12:40*pm, Florian Weimer wrote:
> I tested this again after a couple of years, and the behavior doesn't
> seem to have changed: If a Berkeley DB database is written using TDS
> with a reasonably sized cache, data is written from the cache to the
> file system in what a appears to be a random fashion. *Apparently, a lot
> of holes are created, which are then filled. *This degrades file system
> performance and makes hot backups somewhat difficult (because the read
> performance is a fraction of that what can actually achieved).
>
> Is there still no way to preallocate the contents of B-tree files?
>
> (Without TDS, the problem disappears, it seems to be related TDS or the
> cache size.)


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  #3  
Old 07-21-2008, 04:33 AM
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Default Re: File system fragmentation

* wawawawa:

> post to http://forums.oracle.com/forums/forum.jspa?forumID=271
> they have bdb dev taking questions


Some Sleepycat folks used to be around here, too.

Registering for forums is always a bit of a hassle, and they require
tons of informatio$n.
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  #4  
Old 07-21-2008, 04:33 AM
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Default Re: File system fragmentation

* wawawawa:

> post to http://forums.oracle.com/forums/forum.jspa?forumID=271
> they have bdb dev taking questions


Some Sleepycat folks used to be around here, too.

Registering for forums is always a bit of a hassle, and they require
tons of information.
Reply With Quote
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