在连接到RDS实例的EC2实例上，我遇到了性能不理想的情况。 这个特定的实例是在VPC存在之前build立的，所以所有的stream量都stream经一个虚拟网卡。
stream量configuration文件保持在200mbit / s左右，并突发到演出线的全部容量5-10秒，这是所有入站MYSQLstream量（突发）。 相比之下，HTTP前端stream量相当轻。
直到最近，爆发导致TCP拥塞崩溃。 我相信已经解决了，但是我相信还有很多调整的机会。 我很乐意投入工作，但我希望有一个具有良好的networking/塑造知识的人将指向我接下来的目标。
这是我迄今为止所做的：
我改变了TCP拥塞和接收窗口是10（从3 – Linux服务器）
我用静态路由做了这个：
ip route show 10.xxx/26 dev eth0 proto kernel scope link src 10.xxx 169.xxx/16 dev eth0 scope link metric 1002 default via 10.xxx dev eth0 initcwnd 10 initrwnd 10 这似乎可能缓解了最严重的TCP拥塞崩溃。
我也优先使用tc MYSQLstream量出站：
tc qdisc add dev eth0 root handle 1: prio tc filter add dev eth0 protocol ip parent 1: prio 1 u32 match ip dport 22 0xffff flowid 1:1 tc filter add dev eth0 protocol ip parent 1: prio 1 u32 match ip dport 3306 0xffff flowid 1:1 tc filter add dev eth0 protocol ip parent 1: prio 1 u32 match ip protocol 1 0xff flowid 1:1
这似乎使应用程序在拥塞时期更好地响应。 但是，我们监视与数据库，HTTP后端和java邮件的连接，现在在这些拥塞期间，它们往往会受到更多的影响，这是有道理的。
所以我正在进行TCP调整，但由于HTTP和MYSQLstream量是非常不同的，我不知道我应该下一个目标。 这是从正常运行3天的netstat -s。 我不相信我们这个时候已经崩溃了。
netstat -s Ip: 699681065 total packets received 2 with invalid addresses 0 forwarded 0 incoming packets discarded 699681063 incoming packets delivered 594010173 requests sent out Icmp: 938 ICMP messages received 19 input ICMP message failed. ICMP input histogram: destination unreachable: 885 timeout in transit: 10 redirects: 2 echo requests: 41 58 ICMP messages sent 0 ICMP messages failed ICMP output histogram: destination unreachable: 17 echo replies: 41 IcmpMsg: InType3: 885 InType5: 2 InType8: 41 InType11: 10 OutType0: 41 OutType3: 17 Tcp: 130279 active connections openings 6710364 passive connection openings 32963 failed connection attempts 42347 connection resets received 922 connections established 697481982 segments received 591322387 segments send out 489523 segments retransmited 46 bad segments received. 298575 resets sent Udp: 2489966 packets received 17 packets to unknown port received. 0 packet receive errors 2490045 packets sent UdpLite: TcpExt: 4690 SYN cookies sent 1375 SYN cookies received 139230 invalid SYN cookies received 3720 resets received for embryonic SYN_RECV sockets 5703049 TCP sockets finished time wait in fast timer 6814 packets rejects in established connections because of timestamp 21888759 delayed acks sent 2610 delayed acks further delayed because of locked socket Quick ack mode was activated 75329 times 6082 times the listen queue of a socket overflowed 6082 SYNs to LISTEN sockets ignored 269160054 packets directly queued to recvmsg prequeue. 4952741078 packets directly received from backlog 34676003473 packets directly received from prequeue 459594123 packets header predicted 39118686 packets header predicted and directly queued to user 65528973 acknowledgments not containing data received 198865300 predicted acknowledgments 124 times recovered from packet loss due to fast retransmit 47018 times recovered from packet loss due to SACK data 1175 bad SACKs received Detected reordering 1842 times using FACK Detected reordering 1579 times using SACK Detected reordering 14 times using reno fast retransmit Detected reordering 1756 times using time stamp 2698 congestion windows fully recovered 22329 congestion windows partially recovered using Hoe heuristic TCPDSACKUndo: 25842 11272 congestion windows recovered after partial ack 40247 TCP data loss events TCPLostRetransmit: 3190 71 timeouts after reno fast retransmit 13024 timeouts after SACK recovery 3134 timeouts in loss state 123997 fast retransmits 19821 forward retransmits 61024 retransmits in slow start 122970 other TCP timeouts TCPRenoRecoveryFail: 55 3400 sack retransmits failed 35 times receiver scheduled too late for direct processing 72038 DSACKs sent for old packets 149 DSACKs sent for out of order packets 127535 DSACKs received 146 DSACKs for out of order packets received 38801 connections reset due to unexpected data 2113 connections reset due to early user close 14160 connections aborted due to timeout TCPSACKDiscard: 1131 TCPDSACKIgnoredOld: 981 TCPDSACKIgnoredNoUndo: 12538 TCPSpuriousRTOs: 480 TCPSackShifted: 137435 TCPSackMerged: 314085 TCPSackShiftFallback: 254120 TCPChallengeACK: 3281 TCPSYNChallenge: 8 TCPFromZeroWindowAdv: 16084 TCPToZeroWindowAdv: 16084 TCPWantZeroWindowAdv: 83130 IpExt: InOctets: 624006853592 OutOctets: 370712171692
这里是我目前的sysctl：
# Kernel sysctl configuration file for Red Hat Linux # # For binary values, 0 is disabled, 1 is enabled. See sysctl(8) and # sysctl.conf(5) for more details. # Controls IP packet forwarding net.ipv4.ip_forward = 0 # Controls source route verification net.ipv4.conf.default.rp_filter = 1 # Do not accept source routing net.ipv4.conf.default.accept_source_route = 0 # Controls the System Request debugging functionality of the kernel kernel.sysrq = 0 # Controls whether core dumps will append the PID to the core filename. # Useful for debugging multi-threaded applications. kernel.core_uses_pid = 1 # Controls the use of TCP syncookies net.ipv4.tcp_syncookies = 1 # Disable netfilter on bridges. net.bridge.bridge-nf-call-ip6tables = 0 net.bridge.bridge-nf-call-iptables = 0 net.bridge.bridge-nf-call-arptables = 0 # Controls the default maxmimum size of a mesage queue kernel.msgmnb = 65536 # Controls the maximum size of a message, in bytes kernel.msgmax = 65536 # Controls the maximum shared segment size, in bytes kernel.shmmax = 68719476736 # Controls the maximum number of shared memory segments, in pages kernel.shmall = 4294967296