Plone 4 data is stored on the file system rather than in the database?

According to this post: http://ifpeople.wordpress.com/2010/10/20/plone-4-best-yet-of-the-best-cms/

There is words about data storage:

Plone 4′s capacity to handle very large files has improved drastically since all file data is now stored on the file system rather than in the database. This enhances the ability of Plone to scale to handle huge content repositories out of 开发者_开发百科the box!

I'm not plone user. What the meaning of that words? Is it flat file database?

Instead of storing uploaded pdfs and so in the database, these are now stored in a regular file system folder.

So they're stored as regular files on the regular filesystem. Plone's database itself handles those files transparently, so the application code doesn't need to know whether the files are on the filesystem or inside the database. (The technical term is "BLOB storage": binary large objects).

And, yes, it helps a lot with performance :-)

For another explanation, see point 4 on http://jstahl.org/archives/2010/09/01/5-things-that-rock-about-plone-4/ .

By default, files and images uploaded to a Plone 4 site are no longer stored in the traditional 'filestorage' file (eg. Data.fs), but instead in a specially organised 'blob' storage area on the file system. This is a tremendous help in preventing huge Data.fs files. Everything else is in stored the filestorage as before. The only thing you need to worry about is how to do backups properly, as repozo doesn't support this :-)

No, this quote refers to the inclusion of ZODB "blob support" (http://en.wikipedia.org/wiki/Binary_large_object) in Plone 4. Prior to this release, objects like files and images were stored in the (flat file) Data.fs file (which is part of the ZODB).

Now, they are stored on the filesystem in files (still managed by the ZODB) that look like this:

var/blobstorage
var/blobstorage/.layout
var/blobstorage/0x00
var/blobstorage/0x00/0x00
var/blobstorage/0x00/0x00/0x00
var/blobstorage/0x00/0x00/0x00/0x00
var/blobstorage/0x00/0x00/0x00/0x00/0x00
var/blobstorage/0x00/0x00/0x00/0x00/0x00/0x00
var/blobstorage/0x00/0x00/0x00/0x00/0x00/0x00/0x3b
var/blobstorage/0x00/0x00/0x00/0x00/0x00/0x00/0x3b/0xa5
var/blobstorage/0x00/0x00/0x00/0x00/0x00/0x00/0x3b/0xa5/0x038ba9d72acbdcdd.blob
var/blobstorage/0x00/0x00/0x00/0x00/0x00/0x00/0x3b/0xa9
var/blobstorage/0x00/0x00/0x00/0x00/0x00/0x00/0x3b/0xa9/0x038ba9d836b5cdaa.blob