Chris Withers wrote:
Dario Lopez-Kästen wrote:

I am in need for some help. We are using Zope 2.6.2, DBTab on the clients (4 of them on 2 servers) and Directory storage on teh ZEO side.

Out of interest, why are you using DirectoryStorage?

I chose it for several reasons:

1) we are storing large amounts of binary files (PDF, Word, Matlab, Zip, tar-balls, etc) in this particular application (it's a student portal, course admin portal and an LMS). While we are not yet in the multigigabyte realm, we are storing archive copies of all the previous year's materials, which will eventually grow to be a lot of stuff.

2) There is the issue of huge Data.fs fiels and making daily backups. We need to have incremental backups

3) HA - while DirStor is not a HA-tool per se, it provides the necessary tools for building something that provide some aspects of HA, ie. the replication features, etc.

4) Maintenance. While I have not yet dared to pack the DB, the mere size of the database will make packing a non-trivial operation memorywise in FielStorage. DirStor does not have the same memory requirements when packing.

5) POSKeyErrors. We where getting quite a few of those, and that scared me. with DirStor, I do not see them as much as before.

Well, ZEO storage server is single threaded, so I guess something could lock there causing the other clients to wait infinitely for the storage server. Never heard of it though. You sure you're using the latest DirectoryStorage? Can you reproduce this using just plain FileStorage?

No, I am not using the latest, because of my *n*l sysadmin (actually there are two of them, but only one whines :-). I'll try beating him in the head a few times, er, I mean, "discuss the issue with him" to make him change his mind.

For practical reasons, there is no way I can replicate this behaviour with FileStorage. That would entail taking the system down for a few days and then take it back up again after we've moved all the contents to FileStorage.

Today I discovered that the problem may not be in the Zope layer but in the Oracle layer, not because DCOracle or Oracle suck, but because we share our instance with another app that is known for it's bad programming style.

And our app is not the most brilliant piece of code either. Several parts of it have not been touched since before the introduction of Script(Python) in Zope, and back then we were all Zope newbies using DTML for everything.

So there may be DB congestion issues at the core of it all. The reason I sent the mail is that this is something that has been happenning all of a sudden for three weeks now. I'll report back when I get a full report from the DBA guys and see if there is any change in usage pattern on the DB level.



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Dario Lopez-Kästen, IT Systems & Services Chalmers University of Tech.
"...and click? damn, I need to kill -9 Word again..." - b using macosx
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