(Speaking from a Universe perspective, but I think the issues are the same.)
If you are updating a file on one server, and reading it on another, you will probably encounter structural inconsistencies within groups if you do not use U2 NFA. This is due to the fact that groups could be in the process of being modified at the same time that they are being read by the second server. If you are using dynamically hashed files, then information about the modulo and load is stored in the file header, which is cached in memory and updated to disk when the file is closed. The changes in the modulus that occur during update will not be reflected in the header cached on the "read only" machine. There is also a possibility that the "read only" machine could overwrite the header of the file with out of date information. If this occurs, then the file will be physically corrupt, with some records being unreachable. -Rick Nuckolls Lynden, Inc Seattle, WA On Nov 30, 2009, at 10:55 AM, Paul Parkinson wrote: > Thanks for the advice. > > I am only accessing the data on server A for reading. The only updates that > take place are on server A. > > Kind Regards > Paul Parkinson > Director, Ideal Business Services Ltd > mob: +1 758 721 4487 (Caribbean) > skype: 0161 408 2098 > eml: [email protected] > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Wally Terhune > Sent: 30 November 2009 14:32 > To: U2 Users List > Subject: Re: [U2] Mapping files. > > I wanted to underscore what one other poster mentioned... > > If you are actively running UniData on two different servers, the only safe > way to access a UniData file on the 'other' server is via NFA. The reason > for this is that all file access controls (group locks and record locks) are > maintained in local shared memory (Windows memory mapped files). You can > likely make Windows shares work, but you risk corrupting your data files > with concurrent access from two different servers. A udt process on Server A > does not have any knowledge of a udt process on Server B accessing the same > file on Server A (or vice versa). > > Take care... > > Wally Terhune > U2 Support Architect > Rocket Software > 4700 S. Syracuse Street, Suite 400 **Denver, CO 80237 **USA > Tel: +1.720.475.8055 > Email: [email protected] > Web: www.rocketsoftware.com/u2 > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Paul Parkinson > Sent: Monday, November 30, 2009 10:13 AM > To: 'U2 Users List' > Subject: Re: [U2] Mapping files. > > Thanks for your help people. I enquired about the licence for NFA and at 2 > grand per server I think I'll work around it somehow. I hate being ripped > off > > Kind Regards > Paul Parkinson > Director, Ideal Business Services Ltd > mob: +1 758 721 4487 (Caribbean) > skype: 0161 408 2098 > eml: [email protected] > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Colin Alfke > Sent: 30 November 2009 12:30 > To: 'U2 Users List' > Subject: Re: [U2] Mapping files. > > This works for me: > > 001: F > 002: \\SERVERNAME\UNIDATA\Datadir\FileName > 003: \\SERVERNAME\UNIDATA\DictDir\D_FileName > > Both are ud 7.1.6 one on XP and one on win 2003 (remote) and the D:\unidata > dir is shared as unidata. Of course, if it's a DIR file you need to update > <1>. > > Hth > Colin Alfke > Calgary, Canada > > -----Original Message----- > From: Paul Parkinson > > I have 2 servers both running Unidata 7.1 on Windows 2003. In an > application on server "A" I want to access data held in an application on > server "B" > > I have tried the voc entry in the application on serverA > > 001: F > 002: \\serverB\unidata\filename <file:///\\serverB\unidata\filename> > 003: \\serverB\unidata\D_filename <file:///\\serverB\unidata\D_filename> > > I have also tried replacing "serverB" in the above with the IP address > But I get the error "open file error no such file." > Anyone know what I should be doing? > > Paul Parkinson > > > _______________________________________________ > U2-Users mailing list > [email protected] > http://listserver.u2ug.org/mailman/listinfo/u2-users > > > _______________________________________________ > U2-Users mailing list > [email protected] > http://listserver.u2ug.org/mailman/listinfo/u2-users > _______________________________________________ > U2-Users mailing list > [email protected] > http://listserver.u2ug.org/mailman/listinfo/u2-users > > > _______________________________________________ > U2-Users mailing list > [email protected] > http://listserver.u2ug.org/mailman/listinfo/u2-users _______________________________________________ U2-Users mailing list [email protected] http://listserver.u2ug.org/mailman/listinfo/u2-users
