Oracle and DB2 recommends setting following kernel parameters as
system preparation before db engine installation:
kernel.shmall = 2097152
kernel.shmmax = 2147483648
kernel.shmmni = 4096
kernel.sem = 250 32000 100 128
net.core.rmem_default = 262144
net.core.rmem_max = 262144
net.core.wmem_default = 262144
net.core.wmem_max = 262144
fs.file-max = 65536
net.ipv4.ip_local_port_range = 1024 65000

Do you have any experience with abovementioned parameters and their
impact to Firebird database?

Kindly regards,
Kevin Smith