Stuart McLachlan
stuart at lexacorp.com.pg
Tue Oct 21 16:42:53 CDT 2003
I know we don't use ithem very often these days, but there are still such things as Random Access files :-) OPEN "myfile" FOR RANDOM SHARED AS #1 LEN = xxx where xxx = the max length ot the line you will be writing Then have each PC write to a different record number On 21 Oct 2003 at 15:32, Martin Reid wrote: > Anyone have any ideas re the following? > > I have a system whereby each PC in the SCCs sends in one short line per > minute to a central server. Each line is of the form IP address, time, > date[, user id]. The central server is only a P450 with 256Mb memory but > I have used a P733 with the same results. > > When a user logs in to a PC, it writes a line to the same file on the > central server as all the other used PCs. Each PC writes at the same > second each minute, but the PCs determine their second to write by > chance, basically. Thus the incoming data for the file is reasonably > well spread across 60 seconds. > > On the minute, the software on the central server renames the input > file, thereby causing a new one to be created with the next record sent > to it. The central file is held on a share to which each PC has to > authenticate. > > When enough PCs are active, and I have not been able to deduce if there > is a threshold figure for that number, some or most of a record may be > lost. That can be seen from the input files. > > During stress tests, when my PC was the only system communicating with > the server, My PC could send in about 630 lines per minute and none > would be lost. And this over a period of say an hour. However, when > multiple PCs send in lines, the data loss may arise with 50 PCs active. > The difference is the number of active network connections. > > As I don't believe the data is being lost on the network (I have > monitored this and have not seen losses so far), it is most likely being > lost through the networking code/file system combination, and probably > the former. > > I was wondering if anyone had a better method for collecting this > asynchronous auditing information, one which did not lose data. > _______________________________________________ > dba-Tech mailing list > dba-Tech at databaseadvisors.com > http://databaseadvisors.com/mailman/listinfo/dba-tech > Website: http://www.databaseadvisors.com -- Lexacorp Ltd http://www.lexacorp.com.pg Information Technology Consultancy, Software Development,System Support.