File system fragmentation

#1

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.)

#2

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 <f... (AT) deneb (DOT) enyo.de> wrote:

Quote:

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.)

#3

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 <f... (AT) deneb (DOT) enyo.de> wrote:

Quote:

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.)

#4

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 <f... (AT) deneb (DOT) enyo.de> wrote:

Quote:

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.)

#5

* wawawawa:

Quote: