Nikolay Samofatov wrote about his Large Iron production systems that he maintains :
We run Firebird to power larger systems (for 12 government agencies and 3 banks).
It has approximately 100000 end users multiplexed through 2500 (max) pooled connections.
Here is the snapshot of nearly idle system at night:
top - 03:20:39 up 10 days, 8:39, 7 users, load average: 2.08, 1.87, 2.15
Tasks: 1732 total, 1 running, 1730 sleeping, 1 stopped, 0 zombie
Cpu(s): 11.9%us, 4.0%sy, 0.0%ni, 83.5%id, 0.0%wa, 0.0%hi, 0.6%si, 0.0%st
Mem: 529177288k total, 378587600k used, 150589688k free, 761532k buffers Swap: 1073741816k total, 130612k used, 1073611204k free, 333281232k cached
[root mvv bin]# ps aux | grep -c rdb_inet_server
Database is on a small FusionIO drive:
/dev/fiob on /mnt/db type ext2 (rw,noatime)
/dev/fiob 587G 423G 135G 76% /mnt/db
Also later he mentions that he uses 2TB of RAM machines
Chipsets that can handle 2 TB of RAM and 8 CPU sockets (<=80 cores, <=160 threads) are the largest “commodity” type hardware available now. These are the largest systems we worked on. 8 GB of lock manager space per database should be just enough for them. With the allocation error check in place we’ll have this problem solved for the next year or two until larger systems become common.