Navision Backup Very Slow after SP6a Applied

We have a Navision DB (US 2.01.B) running on an NT 4 server (dual 500 MHz processors, 528 MB RAM) using RAID 5. The DB is currently 4.9 GB divided into 3 files of 2 GB, 2GB and 900 MB. Up until 1 week ago the server was running SP5. We upgraded to SP6a in preparation for the installation of WINS and the addition of another subnetwork. On attempting to run the daily Navision backup that evening, we noticed that only 1% was completed after 10 minutes (the backup usually takes 35 minutes). We tried restarting the service, rebooting the server, expanding the database to increase the free space, all with no improvement. The next evening we let the backup run all night; the next morning it had only completed 46%. Our NSC has contacted Navision USA, but they don’t have any ideas yet. We’re hoping that one of you does. Thanks, Caryn

Possible Networking Problem. Test by running the backup on the server. Does it go faster? If slow on the server, perhaps you have a problem with RAM configuration. Check frequency of page faults. Please let us know what you discover. Jim.

The backup does run on the server. The networking configuration hasn’t changed. We did however back out SP6a, but this has had no effect whatsoever. The only change we can link to this situation was the application of SP6a 6 hours before the problem first occurred.

The backup does run on the server. The networking configuration hasn’t changed. We did however back out SP6a, but this has had no effect whatsoever. The only change we can link to this situation was the application of SP6a 6 hours before the problem first occurred.

The backup does run on the server. The networking configuration hasn’t changed. We did however back out SP6a, but this has had no effect whatsoever. The only change we can link to this situation was the application of SP6a 6 hours before the problem first occurred. I’ll check on the page faults.

The backup does run on the server. The networking configuration hasn’t changed. We did however back out SP6a, but this has had no effect whatsoever. The only change we can link to this situation was the application of SP6a 6 hours before the problem first occurred. I’ll check on the page faults.

Caryn, I don’t understand. Let me try to me clarify my question… Do you physically go to your server and run the Navision client on the server and try to do a backup? When you do this (involving only one computer so traffic does not pass through any network interface) does the backup run fast? Jim.

Caryn, Also, if you run the backup from a computer (not the server) does it run faster then? Jim.

Even though you only installed SP6a, and nothing else, there is always something else. Sometimes it is just that there was that one other thing. Things you should check, are if the cache parameters on the Navision server weren’t changed. Does the machine have IIS installed, if so check for some virus such as “W32.Nimda.A@mm” causing the machine to slowdown. Also maybe you installed something some time ago, but since then have not re-booted the server, and now that program is taking effect. My experience has generally shown that the application of a service pack either kills Navision completely, or has no effect. By the way, just a word of advice, if your server is running OK, you really should never apply service packs. As they say, “if it ain’t broke, don’t fix it”. _________________________ David Singleton Navision Consultant since 1991 dmks22@home.com___________

I run the client on my PC, the backup runs on the server and the data is written to the server; no data crosses the network. Page faults look a little on the high side, but I’m not an expert. What is strange is a few days ago we discovered that Navision was running 4 instances of slave.exe (we don’t know since when). One instance was using 18MB of RAM, the others about 1MB each. Today 3 of them are using 83-89MB of RAM each and the fourth is using 28MB. The users say response time is normal. I’d appreciate your input on this since our NSC seems to have disappeared. Thanks, Caryn

Caryn, You run the client on your PC? If you are running Navision on your PC and you are selecting “Backup” then the data is moving across the network twice. Once from the server to your PC and then back to the server. To do the test I’m suggesting you need to go to the server and run the Navision client from there. Then from that client, try to do a backup and see what happens. We may just have trouble communicating here but I’m still not sure we are in synch on exactly what you are doing. You need an NSC to look at the memory allocation to see if you have too much Cache or if some other process is now taking up memory that used to be used by Cache. Yoru NSC or other Navision professional might try testing cache at zero to see if that makes the backup go faster. Unless you know what you are doing, I’m not sure you should alter your server settings. You don’t want the problem to get worse. Good Luck Jim. Edited by - jim hollcraft on 2001 Sep 21 05:12:39

quote:


since our NSC seems to have disappeared


oops… Slave.exe is a programme that moves data from the Navision Commitcace to the Navision database. You should have one instance running for each database part. You stated that you have three database parts so you should see three instances of Slave.exe running. One problem is that you have different sized database parts, and to me that often indicates that your disk configuration is incorrect and I see you are using RAID 5, which is definitely a BAD thing. You really should have more individual disks in this configuration. Try the attached Form, it can be used to see the load balance across your database parts: David Singleton Database disk balance _________________________ David Singleton Navision Consultant since 1991 dmks22@home.com___________

Caryn, Did you solve the problem? Please let us know what caused it. Jim.

I thank everyone for your responses. Our NSC suggested increasing cache (from (96MB to 200MB), which had no effect. Thanks to Jim’s persistence I decided to run the backup from a client on the PDC even though our NSC said no data was crossing the network. The backup ran in 20 minutes. This did indeed indicate a network problem, as suggested in some of your responses. It turns out that the day the problem first occurred was also the day when my PC was taken off its direct connection to the switch and moved to a hub. I confirmed the impact of this change by reconnecting my PC directly to the switch and running the backup from my PC: it ran in 30 minutes!. Thanks again for all your input, Caryn

Hi Caryn, its is great that you have solved your immediate problem. Be aware that Navision is a Client server application, so as Jim pointed out, it is very important that you are aware of the network traffic involved in any particular task. And as I mentioned before, when things slow down, it is not allways a clear cut problem, more a case of a number of issues combined together. On another point, you should look at the database configuration you have. The RAID 5, and three different sized database parts, and the multiple slave.exe instances should be resolved. Please speak with your NSC about these. _________________________ David Singleton Navision Consultant since 1991 dmks22@home.com___________

Ok, a few of you have posted that running RAID 5 is a bad thing. I am under the understanding that using RAID 5 with a database is a great thing. What’s wrong with RAID 5?

With SQL Server RAID is a fine thing. With the native database RAID can cause problems when the database extends into multiple files due to data allocation methods across the database files within Navision itself. With just one file there is no problem that Ive ever seen other than the performance hit. In current installations of some of our clients, those that run RAID 5 with one database have a quick system even with high user numbers (50-100) so it all depends on the hardware and the configuration. Craig Bradney Technical Manager Navision Solutions & Services, Deloitte Touche Tohmatsu Email:cbradney@deloitte.com.au

With the native database You shall allways use RAID-1. This is some expensive but gives You much better performance since You get a cache for each physical disk in Navision. You also don’t have the overhead as in RAID-5. RAID-1 is also recommended by Navision //Lars

Thank you for the clarification on RAID 5. We are using SQL 7.0, 2 files. One on the RAID subsystem and one on a mirrored drive. It took me by surprise when I read that people were AGAINST RAID 5, but knowing all the details sure makes it easier. Glenn.