#It is recommended to haveaminimum of256as value forevery4MBof RAM you have.
#It sets the maximum number of shared memory segments that server can handle.
#As Oracle recommends the value should be at least4096,
#it says that we cannot find more than4096number of shared memory segments at any instance on the server.
#Note that SHMMNI value is innumbers.
#No change it should be4096.It must be increased ifyou have more than at least one fourth(1024)Oracle Databases running on the server.Which we never recommend.
#It defines the total amount of shared memory PAGES that can be used system-wide.
#It means that to the use all the physical memory this value should be less than or equal to total physical memory size.
#ForDBA's, it means that sum of all SGA sizes on the server should be less than or equal to SHMALL value.
# Note that SHMALL value is a number of pages.
# If you want the maximum size of SGA on this server to be 5GB, then this parameter value should be 5*1024*1024*1024 = 5368709120 bytes. This, in turn, says that you should not have any database with more than 5GB of SGA. But you can have multiple databases with each 5GB of SGA or even less. This is the fact why Oracle recommends to have this value more than half of the memory to utilize it for SGA(s).
# By chance, if your SGA size is more than 5GB say it is 7GB then 2 shared memory areas will be allocated to SGA with one of 5GB and two of 2GB sizes, which doesn'sperform well.
#It defines the total amount of shared memory PAGES that can be used system-wide.It means that to the use all the physical memory this value should be less than or equal to total physical memory size.ForDBA's,it means that sum of all SGA sizes on the server should be less than or equal to SHMALL value.Note that SHMALL value isanumber of pages.
#By default the page size on Linux is4KB.The total size of RAM is8GB.Let usleave at least1GBof RAM forLinux kernel to run,with which consider7GBcan be used forOracle Databases.Now value of SHMALL can be:
#This parameter defines the range of port numbers that system can use forprograms which want to connect to the server withoutaspecific port number.
#Now,it makes sense ifyou have come across somebody advising you not to use port numbers forlistener beyond9000.Also,just look back to documents on OEM installation,Oracle uses and advises all the default port numbers less than9000.
#This parameter defines the default and maximum RECEIVE socket memory through TCP.
#This parameter defines the default and maximum SEND socket memory through TCP.