Re: Database vs FileSystem (a comparison)

Don't know about a paper. Therefore just some thoughts.

Storage: stored as blob you need the size of the blob in a tablespace (ofcourse), otherwise the same space would be needed on the filesystem. As blob there is the overhead of the lobindex and some more bytes too I suppose. When on filesystem there is the overhead of the bref reference to the file. Can't give you any numbers.
Since the blobs are much larger than the real table, make sure the entire table or only the lob column is stored in a proper tablespace (maybe dedicated to the table or lob column). When the lob column is in a special tablespace create it with the proper storage clause because you can only change it by export/drop/create/import. The alter table command has no alter storage option for the lob column.

Security: on filesystem the data is not completely protected by Oracle access mechanisms (you can even set up access to the row level with fine grained access). With the proper privileges on the OS access is possible too.

Performance: I don't know, I just guess it makes not much difference. Blobs are usually large and you need the IO anyway. Difference is the way Oracle deals with blobs versus external files and I can't say anything about it.

Scalability: ?

Consistency: when stored on filesystem the binary files are no part of a recovery. Suppose you need to restore the database and do an incomplete recovery to a point in time. You can have binary files on the filesystem that are no longer registered in the db (inserts after the recover timestamp) or there can be references in the database to no longer existing files (deletes after the recover timestamp). This could be the reason that forces you to choose a storage as blob. The blob should be created "logging".

José Arango <arango_at_caribe.net> schreef in berichtnieuws uo599gpa3bch16_at_corp.supernews.com...
| Hello everyone,
|
| I'm interested in learning the main differences between storing binary
 files
| (BLOB's) on a databae vs a filesystem. I would like to know the difference
| in many aspects: storage, security, performance, scalability etc.
|
| Can anyone point me to the right direction? any good site, whitepaper? I
| did a search on Google (both Web & Usenet archive) but unfortunately there
| isn't much out there.
|
| Thanks in advance,
| José
Received on Sat Sep 14 2002 - 14:49:35 CDT