# 256 KB default performs well experimentally, and is often recommended by ISVs. net.core.rmem_default = 262144 net.core.wmem_default = 262144 # When opening a high-bandwidth connection while the receiving end is under # memory pressure, disk I/O may be necessary to free memory for the socket, # making disk latency the effective latency for the bandwidth-delay product # initially. For 10 Gb ethernet and SCSI, the BDP is about 5 MB. Allow 8 MB # to account for overhead, to ensure that new sockets can saturate the medium # quickly. net.core.rmem_max = 8388608 net.core.wmem_max = 8388608 # Allow a deep backlog for 10 Gb and bonded Gb ethernet connections net.core.netdev_max_backlog = 10000 # Always have one page available, plus an extra for overhead, to ensure TCP NFS # pageout doesn't stall under memory pressure. Default to max unscaled window, # plus overhead for rmem, since most LAN sockets won't need to scale. net.ipv4.tcp_rmem = 8192 87380 8388608 net.ipv4.tcp_wmem = 8192 65536 8388608 # Always have enough memory available on a UDP socket for an 8k NFS request, # plus overhead, to prevent NFS stalling under memory pressure. 16k is still # low enough that memory fragmentation is unlikely to cause problems. net.ipv4.udp_rmem_min = 16384 net.ipv4.udp_wmem_min = 16384 # Ensure there's enough memory to actually allocate those massive buffers to a # socket. net.ipv4.tcp_mem = 8388608 12582912 16777216 net.ipv4.udp_mem = 8388608 12582912 16777216