Nav 5 and Quad core performance

Business Central/NAV Technical Forum
1

We are currently doing an upgrade from Nav 4.0 on SQL 2k to Nav 5 on SQL 2k5 SP2.

We are currently in the testing phase of the upgrade and our server is crawling.

server is a Dell poweredge 2950 with the following setup:

2 Intel Xenon X5355 Quad core processors

Aray 1 is raid 1 with 2 SAS 73GB 15K drives - OS - Win 2k3 SP2 32bit SQL 2k5 SP2 with logs on this drive

Aray 2 is raid 10 with 4 SAS 146GB 15K drives - DB data files only. Nav DB is 45GB and is divided into 4 data files

SQL is set to Manage Processor and Core affinities

When testing the server I had 10 users putting in orders and running reports following testing scripts.

I watched the processor utilization and all activity was only on 1 core.

I then tested our ebridge software wich is an EDI interface and its activity was not issolated.

We use lightspeed for backups and I switched it to use the SQL backup engine and ran backups and again all cores were used.

any thoughts?

2

This is very typical for a NAV implementation on SQL Server.

NAV uses a fat client which does all the processing. It sends out very simple queries to SQL with the result that CPU utilisation is zip compared to ‘normal’ SQL systems.

Don’t worry to much about it and try to focus on Disk I/O and network bandwith.

If you have client machines that do large processing you might want to consider upgrading them.

3

Hi

Because of the way navision locks tables it is very easy when everybody is doing simular things for the transactions to become serialised, that is they happen one after the other rather than them all happening at the same time and this is especailly true for table writes. So what happens is the first transaction will lock a table (quite often the number series table) and the next process will then try and lock the table and when it can not it waits for the first process to finish before it starts.

I think this is what you could be seeing here.

Regards

Paul

4

That might be one of your problems right there. With the logs on the most active drive array, it is wonder it is slowing down. It is recommended that the transaction log is on its own dedicated array. This means nothing but the transaction log for the NAV production database. Put anything else on that drive, like backups, or transaction logs of other databases, and you adversely affect the performance of your NAV production database.