[Zope] storages comparation

[Toby Dickenson]

On Friday 17 October 2003 16:23, Alexis Roda wrote:

> here we are planning to migrate our webs from apache to zope. My
> question is about alternate storages 

The feature comparison matrix is here:

http://cvs.zope.org/ZODB3/Doc/storages.html?rev=1

> * tools to recover corrupted databases

What sort of problems are you trying to recover? FileStorage can limp along 
after surviving alot of damage in, for example, a bad disk, bad application 
software, or FileStorage bugs. If your application is such that you can 
recreate any lost data, then you can often perform a repair within the 
application. BDBStorage benefits from BDB robustness in defending against bad 
disks, for example you can store log files and database on different disks, 
but you will need to be a BDB guru to recover from a bad application or 
storage bugs. DirectoryStorage is similar to FileStorage in surviving damage, 
but it has stricter input validation. It is intentionally less tolerant of 
problems that *might* cause problems, prefering to raise an error rather than 
risk a corruption. This is good if you absolutely must not loose data, but 
bad if availability is more important and you can afford to fix any minor 
data loss.

> * tools for backup

See that feature comparison matrix above for the details. FileStorage has a 
pretty good incremental backup tool, although the file format doesnt make 
this elegant. Data backup is what DirectoryStorage does well - it has backup, 
replication, and checking tools designed in from the beginning. For 
BDBStorage, you get to study the Berkely user manual. It is robust if you do 
it right, but Im not aware of any wrappers to reduce the effort in setting 
this up.

> * fiability

Is that a spelling erorr?. 

> * support for objects, undo ... versions are not important

Then you have a choice of the full range of storages.

> Performance and scalability is not important here.

I hope this helps.

-- 
Toby Dickenson