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From Lily Wei <lily...@yahoo.com>
Subject Re: NFS and Derby
Date Thu, 11 Nov 2010 17:17:44 GMT
I would agree to be safe and able to sleep at night ensure data integration by 
not using NFS mounts database is definitely the way to go.  However, I remember 
there are SAP customers who do that with Oracle. Oracle push the idea to use NFS 
mounts database. I was referring to article like: 
http://www.sun.com/bigadmin/features/articles/7000_oracle_deploy.jsp

Some discussion on SAP community network: 
https://forums.sdn.sap.com/message.jspa?messageID=7964399

DB2 does not recommend such operation. 
http://publib.boulder.ibm.com/infocenter/db2luw/v9/index.jsp?topic=/com.ibm.db2.udb.uprun.doc/doc/c0025100.htm



I will not say I would never put a database (the data files) on an NFS 
filesystem. However, I will think three times before doing that. :)

Lily




________________________________
From: Kathey Marsden <kmarsdenderby@sbcglobal.net>
To: derby-user@db.apache.org
Sent: Thu, November 11, 2010 7:56:25 AM
Subject: NFS and Derby

I have always told users they have to have their databases on a local disk to 
ensure data integrity and that  a system crash for an NFS mounted database could 
cause fatal corruption, but had a user this morning take me to task on this and 
ask me to explain exactly why.  I gave my general response about not being able 
to guarantee a sync to disk over the network, but want to have a more 
authoritative reference for why  you cannot count on an NFS mounted disk 
although I did find several places where the sync option "favors data integrity" 
which certainly doesn't sound like a guarantee.  Does anyone know a good general 
reference I can use on this topic to support my "you gotta use a local disk" 
mantra.


Also I think our documentation on this topic should be a bit stronger.  
Currently we just say it may not work and probably should be clearer that data 
corruption could occur.  I will file an issue to beef up the language based on 
the conversation in this thread.

http://db.apache.org/derby/docs/10.5/devguide/cdevdvlp40350.html

Thanks

Kathey


      
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