Its observed that when we develop applications on Java CAPS up till 5.1.3 the common size of the ear file happens to be 12 -15 MB. Its also observed that when we have normally applications more than 4 - 5 the domain startup time increases. Generally we can not make any difference to the startup time of the domain.
The following are some of the tips which can possibly be followed to bring down the startup time. You should not curse me if this doesn't work out .
1. start the appserver in '-server' mode (JVM options). If this flag is not there, your app server JVM will spin trying to compile all the EAR code.
2. keep your Min and Max heap size the same (e.g. 2GB, what ever we have) to get more efficient heap size allocation and save on time.
3. Another thing to look out for is EAR file size... if all ear's have redundant jar's packaged within them, we can separate them and
put in /lib folder and not embedded in each EAR (class loading delay) --
4. Have you tried to deploy one app at a time and what effect it has on the startup time in case any specific app is taking much longer than
others? --- We can have some pointers here as to which application is taking more startup time.
5. Apart from above since these issues with respect to the performance needs to be seen in isolation we need to look at each of the ear with respect to the startup time. Since this can give a closure look at which application is causing the issue we can have a close look.
Why does the deployment take long time ? -- The application server a.k.a. IS is SJSAS 8.1 version. All the applications of the previous versions of the Java CAPS bundle the "rar" or the connector files with each of the ear file. Also the packaged applications used to create the resource connection pools etc. during the deployment time, which takes considerable time.
That said, I would recommend to move to SJSAS 9.1 for deployment since there has been lot of improvement with respect to startup time, resource pool management, cluster profile, performance etc.
I will cover moving to 6.0 in some other post believe me its simple.
Post your experiences with these options or any other options if there are any...