Koozali.org: home of the SME Server
Legacy Forums => General Discussion (Legacy) => Topic started by: Ray Mitchell on March 15, 2002, 11:19:53 AM
-
Dear All
Can anyone give me a "plain english" summary & perhaps direct me to further information regarding so called "race" conditions and multi user sharing of files in Linux. Is this an issue that is broadly applicable to any Linux OS and/or are there particular issues involved with relation to sme server ? Read below for a summary of my situation.
I am using some Windows accounting/database applications which are multi-user and installed on a network drive . I have set up an ibay on the sme server and mapped that as a drive in Win 95b & 98SE workstations. The program files on the server are accessed via the network (100Mb/hub/UTP) and data files are stored on the server. I receive various error messages generated by the particular program being used, generally relating to problems accessing a file or data corruption. I need to reindex and rebuild these database systems fairly regularly. I also have experienced some slowness when running certain tasks (see comments below).
There are usually 6 to 8 users on the system with between 4 to 8 programs open on each workstation eg Word, Excel plus 4, 5 or 6 versions of the accounting/database programs.
Discussions with the software vendors have only resulted in vague answers, but it would appear that they are aware of these issues when their software is run from a Linux based server OS, and they have stated that the problems seem to have worsened with more recent releases of Linux OS's. They have suggested I use a Windows 2000 workstation running as a file server or alternatively setup a full Windows 2000 Server, and run all their applications from that server.
Rather liking the sme server, I was a bit reluctant but did setup a Win 2000 Pro machine to see if there was any change in performance. The response times using the Win2K Pro PC as a file server were significantly faster than sme server. I also set up a Win95b PC as a file server and the response time using that was similar to the sme server.
eg making a particular selection switching To Do lists
sme 20 secs
win95b 20 secs
win2K 6 secs
Over tha last couple of weeks I am running a sme server for email/gateway/web access/print server and a Win2000 Pro box as file server, and have not been getting any application error messages or had a need to reindex the databases, and application access speeds are quicker.
Note that the hardware used was identical, (ie reloaded the different OS's on the same computer), in fact on one test with Win 2000 I used a much slower processor, old 2.5G hard disk and only 32M RAM, and this PC performed much faster than a more highly spec'd sme server.
In actual fact the hardware platform did not seem to make much difference, a Pent 233/4.5G/32M and a Pent4/1.8GHz/40Gb/512MbRAM both used as Win 2000 Pro servers had the network applications running at similar speeds. It was the server OS that had the biggest effect.
I have discussed this with the software vendors and they say that this particular task is fairly disk intensive and therefore the results do not surprise them. They have designed their software to run well on Windows NT/2000 servers or similar (Netware etc) and are stating that clients who use Linux based servers are the only ones having problems. They are saying that the "race" condition is really the issue, and is responsible for both the data corruption, the error messages and for the slowness ie system can't handle the multiple users requests "correctly" when accessing the same file.
I'm not expecting anyone to troubleshoot my software problems as such, but does anyone have some input/advice/comments re these issues. Is it possible to "speed up" Linux/sme ?
In e-smith and sme I see reference to hdparm, which I believe is something to do with optimising hard disk performance, can anyone advise further here, and would this be likely to improve disk access performance.
Is there a way to get sme and my software to perform at the speed Win2000 and my software perform at ?
I had the impression that a file server should act as a file server no matter what OS it was using, why then the speed differences when using different server OS's ?
Thanks
Ray Mitchell
-
The program that provides the windows file-sharing service is 'samba' and these issues are specific to samba rather than Linux or SMEserver in general. You might get an overall disk performance improvement with hdparm if you are using IDE drives and your hardware supports DMA, but the application specific problems have to do with the many ways Windows clients handle file locking and the ways that samba emulates it. You can probably find some answers (or at least others with the same problems...) by searching the samba mailing list archive at http://marc.theaimsgroup.com/?l=samba&r=1&w=2