Dhcpd4-Daemon uses extremly much ram

Question

Hey there,
I'm using a dhcpd4-daemon on a server which also do radvd, named and run routing. The dhcpd4-daemon uses 60-80% of memory (the system has 512 MB), even right after the start with an empty lease file.
The daemon is configured for 26 subnets with /16 of size each, but there are only about 300-600 clients  (within the lease time of 600 seconds), but the environment is very dynamic.
Is there a reason for this exorbitant memory hungry? Are there comparable alternatives?
ddns-update-style none;
ignore client-updates;
deny declines;
one-lease-per-client true;
ignore bootp;
default-lease-time 600;
max-lease-time 800;
min-lease-time 60;
ignore-client-uids true;
authoritative;
log-facility local7;
subnet 10.66.0.0 netmask 255.255.0.0 {
range 10.66.11.1 10.66.20.255; #main
pool {
range 10.66.1.1 10.66.10.255;
deny all clients;
pool {
range 10.66.30.1 10.66.254.255;
deny all clients;
option broadcast-address 10.66.255.255;
option routers 10.66.11.0;
option domain-name-servers 10.66.11.0;
option ntp-servers 10.66.11.0;
interface subnet-x;
There are 26 identically nets, on other interfaces with other ip-ranges.
Best regards,
Ruben

Answer 1

Well, if I start the daemon with an empty-leasefile it uses the same amount of storage, here for example with a small leasefile:
[root@bragi ~]# pmap -x 3174
3174: /usr/bin/dhcpd -4 -q -pf /run/dhcpd4.pid
Adresse kByte RSS Dirty Modus Zuordnung
0000000000400000 2000 624 0 r-x-- dhcpd
00000000007f3000 4 4 0 r---- dhcpd
00000000007f4000 32 20 16 rw--- dhcpd
00000000007fc000 240 24 20 rw--- [ anon ]
0000000001709000 50980 2100 392 rw--- [ anon ]
00007f758d881000 472112 259264 15928 rw--- [ anon ]
00007f75aa58d000 44 0 0 r-x-- libnss_files-2.21.so
00007f75aa598000 2048 0 0 ----- libnss_files-2.21.so
00007f75aa798000 4 0 0 r---- libnss_files-2.21.so
00007f75aa799000 4 0 0 rw--- libnss_files-2.21.so
00007f75aa79a000 1636 1240 0 r-x-- libc-2.21.so
00007f75aa933000 2048 0 0 ----- libc-2.21.so
00007f75aab33000 16 12 0 r---- libc-2.21.so
00007f75aab37000 8 8 8 rw--- libc-2.21.so
00007f75aab39000 16 12 12 rw--- [ anon ]
00007f75aab3d000 136 124 0 r-x-- ld-2.21.so
00007f75aab67000 1964 252 64 rw--- [ anon ]
00007f75aad5d000 4 4 4 rw--- [ anon ]
00007f75aad5e000 4 4 0 r---- ld-2.21.so
00007f75aad5f000 4 4 4 rw--- ld-2.21.so
00007f75aad60000 4 4 0 rw--- [ anon ]
00007ffee1b13000 132 24 20 rw--- [ stack ]
00007ffee1bd4000 8 0 0 r---- [ anon ]
00007ffee1bd6000 8 4 0 r-x-- [ anon ]
ffffffffff600000 4 0 0 r-x-- [ anon ]
kB gesamt 533460 263728 16468
[root@bragi ~]# du -h /var/lib/dhcp/dhcpd.leases
776K /var/lib/dhcp/dhcpd.leases
But to respond to your thought, if we think of one client is using 5 KByte of data, instead of 400 Bytes, the Server would need to save infos about 600 Clients around 3 MByte, so the question is, why do it need 470 MByte?
Last edited by RubenKelevra (2015-04-06 15:58:01)