ArcSDE instance and performance

[bayramüçüncü]

When I start the server, the instance count of ArcSDE is increasing to 25-30. And some times later the instance count is increasing again and I cannot connect to ArcSDE from ArcMap.

instance clients machines are: arcsde

The error is: Failed to connect to database. Maximum number of connections to instance exceeded

1-what is the reason of the instance increment.
2-Tere are published services from "http://<domain>/arcGIS/Services" url. Is this published count effects?

[VinceAngelo]

Each client uses a connection.  When you start a map service with one connection
in four threads on three servers, it will create 12 connections (1x3x4).  If you have
an Enterprise ArcSDE install, you can increase the number of maximum connections,
but you may be limited to 70-115 application server connections by Windows
(search on "non-interactive desktop heap")

- V

[bayramüçüncü]

Each client uses a connection.  When you start a map service with one connection
in four threads on three servers, it will create 12 connections (1x3x4).  If you have
an Enterprise ArcSDE install, you can increase the number of maximum connections,
but you may be limited to 70-115 application server connections by Windows
(search on "non-interactive desktop heap")

- V

You mean Each map service created 1 instance. But what means "four thread on three server"?

[VinceAngelo · Accepted solution]

The terminology has changed at 10.1, but you haven't said what version you're
using, so I'll stick to the old naming...

So each ArcGIS Server map service can have multiple SOCs, right?  And you can
run multiple copies of each service in each SOC, right?  Well, each one of those
copies (implemented as threads), in each SOC (run on a server) uses one ArcSDE
client connection.

There are times where a server crashes, and the connections aren't cleared in
the ArcSDE instance, so sometimes the seat count will go up, but those extra
clients don't actually have any impact on performance (until you can't start a
new connection because all the seats are used).  There  are a number of
discussion threads on this topic, so there's no reason for me to rehash them
here.

- V