storages comparation
Hi, here we are planning to migrate our webs from apache to zope. My question is about alternate storages to de default all_in_one_big_file. For the last year I'm been using zope with no problems for some small parts of our web, but from time to time I see a message on the list about unrecoverable corrupted storages ... and that makes me very nervous. I would like to hear about experiences with other storages. I'm specially concerned with: * fiability * tools to recover corrupted databases * tools for backup * support for objects, undo ... versions are not important Performance and scalability is not important here. Thanks in advance -- //// (@ @) ---------------------------oOO----(_)----OOo------------------------ Los pecados de los tres mundos desapareceran conmigo. Alexis Roda - Universitat Rovira i Virgili - Reus, Tarragona (Spain) --------------------------------------------------------------------
Alexis Roda wrote at 2003-10-17 17:23 +0200:
here we are planning to migrate our webs from apache to zope. My question is about alternate storages to de default all_in_one_big_file.
Toby Dickenson published a storage comparison matrix. Search Zope.org. Dieter
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
Toby Dickenson wrote:
On Friday 17 October 2003 16:23, Alexis Roda wrote:
* tools to recover corrupted databases
What sort of problems are you trying to recover?
Any? :-) Primarily bugs on *Storage. For bad disks we have tape backups. I've not thought about application errors.
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
Here you mean it can catch application errors?
* fiability
Is that a spelling erorr?.
Yes, my english is not very good. I mean reliability. I think I'll give DirectoryStorage a try ... if I can get it to work. Thanks -- //// (@ @) ---------------------------oOO----(_)----OOo------------------------ Los pecados de los tres mundos desapareceran conmigo. Alexis Roda - Universitat Rovira i Virgili - Reus, Tarragona (Spain) --------------------------------------------------------------------
On Tuesday 21 October 2003 10:22, Alexis Roda wrote:
What sort of problems are you trying to recover?
Any? :-)
Primarily bugs on *Storage. For bad disks we have tape backups. I've not thought about application errors.
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
Here you mean it can catch application errors?
Some errors where the application is breaking some ZODB rules, yes. http://mail.zope.org/pipermail/zodb-dev/2002-October/003405.html -- Toby Dickenson
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Toby Dickenson