OK, what I need to install Dynamics NAV–Part 2

Lets start with the second part.

In the latest post I´ve talked about the memory for the middle tier but we need to check some things about the service.

Each NAV server needs 500 MB of memory to run plus 5 MB per user (active session) even if the sessions are idle and for every page the user opens, you need to allocate more memory.

The server instance has some special parameters to run and give service to the clients.

Data Cache Size – This parameter determines how much memory is used caching data. For a single tenant deployment 9 could be ok.

clip_image001

In NAV 2016 and higher the SQL – NAV interface use ADO.NET instead of ODBC so the resource consumption is lower than prior versions with ODBC.

The cache is a “store in memory” function so when a user read a record, if a second user wants to read the same record, gets it from cache because the cache is shared between the users of the same instance.

NAV use the cache when the system use the following functions

GET

  • FIND
  • FINDFIRST
  • FINDLAST
  • FINDSET
  • COUNT
  • ISEMPTY
  • CALCFIELDS

And there are two types of cache

Global Cache – for all users connected to a Microsoft Dynamics NAV instance.

Private cache – per user, per company, in a transactional scope. Data in a private cache for a given table and company are flushed when a transaction ends.

The cache that is used is determined by the lock state of a table. If a table is not locked than the global cache is queried for data; otherwise, the private cache is queried.

For a call to any of the FIND functions, 1024 rows are cached. You can set the size of the cache by using the Data Cache Size setting in the Microsoft Dynamics NAV Server configuration file. The default size is 9, which approximates a cache size of 500 MB. If you increase this number by one, then the cache size doubles. So, you need to consider how many records can bring back a simple SETRANGE function.

So, from here you can do the math and check how much memory do your Dynamics NAV server needs for one instance and add more memory for development and test instances (if they run in the same server).

Anuncios

OK, what I need to install Dynamics NAV–Part 1

Before the Dynamics NAV installation, we need to check some things related to the infrastructure, users, locations, etc.

Active Directory

Dynamics NAV use AD, SQL and more things like IIS so we need to figure how we can deploy the system, servers and other software. Also, we need to check if the electrical power is consistent or you have many blackouts; same for the internet connection.

Let’s check some scenarios starting with the simplest deployment

Microsoft says that we need an Active Directory. The Active Directory is a very important server because manages all the security and users. For this server you can purchase a low level server with maybe 4-8 GB of RAM, one Xeon processor and a small hard disk (don’t forget the Windows Updates, they need storage space).

This server is queried every time a user tries to access a network share, computer, printer or when you run an application (this is the basic explanation). Nobody recommends to install another service or application in an AD Server so you can buy a cheap server.

Don forget a very basic rule, if you put all the eggs in the same basket, you can lose all your eggs.

So, what can we do? Use to AD Server distributing the FSMO roles in two servers at least. In a Windows environment are five roles

  • Schema Master
  • Domain Naming Master
  • RID Master
  • PDC Emulator
  • Infrastructure Master

You can get more info about these roles in https://support.microsoft.com/en-us/help/223346/fsmo-placement-and-optimization-on-active-directory-domain-controllers

SQL Server

Another server that we need is the Database Server, this server has the SQL Server installation and the database files. We need to check some things for this server:

  • How many Dynamics NAV users are we going to have?
  • How many transactions?

For this server we can start from a dual Xeon based server with 16 GB of RAM for less than 25 users to whatever you can pay.

We need to check the best performance setup for the SQL server, are we going to use SSD or not?

For a SQL server it’s very important to choose the fastest RAID level, the RAID 0 is the fastest because multiple drives are reading and writing data but we don’t have fault tolerance. The fault tolerance can be achieved with RAID 1 which is a “mirroring” RAID. For Dynamics NAV the best approach is to use RAID 10 which combine speed and mirroring and its ideal for highly used database. The problem with the RAID 10 is that you need four drives at least but the SATA and SAS drives prices are getting lower and SSD too.

In SQL Server you need to take into account how many processors and cores you have. Why? Because you can split your log file in partitions and is better to have a log partition in a dedicated disk, as an example, if you have 8 cores, you can split your log file in 8 disk drives (in RAID 10 will be 16) for a better performance.

Also you need to check the SQL Recovery Model, simple, full or bulk logged. https://msdn.microsoft.com/en-us/library/ms189275.aspx

Each model has advantages and disadvantages but the real decision maker point is: do you have personnel with the technical knowledge for use full or bulk logged model? If you don’t have an experienced and dedicated person to do this job, choose the simple model and make daily basis full backups at least.

If you choose the simple model, you can forget the log file partition because the model automatically reclaims log space to keep space requirements small, essentially eliminating the need to manage the transaction log space.

When you are configuring the SQL server, you need to modify some settings in the server’s settings.

Max Server Memory

The buffer pool does not immediately acquire the amount of memory specified in min server memory. The buffer pool starts with only the memory required to initialize. As the Database Engine workload increases, it keeps acquiring the memory required to support the workload. The buffer pool does not free any of the acquired memory until it reaches the amount specified in min server memory. Once min server memory is reached, the buffer pool then uses the standard algorithm to acquire and free memory as needed. The only difference is that the buffer pool never drops its memory allocation below the level specified in min server memory, and never acquires more memory than the level specified in max server memory, this can severely reduce SQL Server performance, with one of our customers, their infrastructure admins top the Max Server Memory to 28 when the server has a 64 total with more than 50 free, all user start to complain until the max memory was free again.

Auto – Create Statistics

This parameter needs to be enabled to allow SQL to tune itself for a better performance.

Auto – Update Statistics

This parameter needs to be enabled to allow SQL to tune itself for a better performance. Also, many C/AL functions relies in these statistics.

Auto-grow

Leave it enabled.

Max Degree of parallelism

NAV queries are OLTP type so it’s very important to set the MAXDOP in 1 for normal use, if you run maintenance jobs, you can change this parameter to 0, run maintenance and return to 1 when its finished.

As a better performance setting, the best setup can be OS and SQL Server in a disk, the database mdf file in another and the ldf in a third disk (all in RAID 10).

Dynamics NAV Server

Here we have the middle tier. Since Dynamics NAV 2013 to 2017, we have the three tier scenario, DB, NAV and client.

According to Microsoft, we need 2 GB of RAM for the server to give access to 5 users, a very small memory amount, the DB needs to be very small.

In a document posted by Microsoft “https://mbs.microsoft.com/Files/partner/NAV/SalesMarketing/MarketingCollateral/MicrosoftDynamicsNAV2013R2SingleTenantOnPremiseSizingGuidelines.pdf “, we have the next statement

clip_image002

So, the NAV Server needs less memory and we can purchase a little server. The document is a great analysis about the transactions and the process time and effort but they don’t check Web Client or Tablet/Phone app besides they don’t install IIS in the testing server.

In this moment we need to start to think about the client access methods, RoleTailored Client, Web client or Tablet/Phone client. Each one has its owns requirements in memory and can affect the server. In the littlest scenario, you install the IIS in the same NAV Server to publish NAV for all of clients and the Help Server too.