在中继搜索中，如果中继过载，中继昵称旁边将显示黄色小点。
这意味着以下负载指标中，至少有一个被触发了：
注意：如果中继达到超载状态，在中继恢复后仍将显示 72 小时。
假若发生中继过载，请执行以下步骤：
查看 https://status.torproject.org/ 的“Tor 网络”（Tor Network）部分，是否存在任何已知问题。
调整系统sysctl优化网络、内存和 CPU 的负载。
启用 MetricsPort了解实际情况。
调整 sysctl 优化网络、内存和 CPU 负载
TCP 端口耗尽
如果遇到 TCP 端口耗尽的问题，可以考虑扩大本地端口的范围。
扩大范围可以用
# sysctl -w net.ipv4.ip_local_port_range="15000 64000"
或
# echo 15000 64000 > /proc/sys/net/ipv4/ip_local_port_range
请记住，如上所述，调整的 sysctl在重启时丢失，而不是永久的。
为了永久有效，需将其添加到 /etc/sysctl.conf 或 /etc/sysctl.d/中的文件。
MetricsPort
想要了解 Tor 中继和 Tor 网络的运行情况，提供并可访问中继指标是至关重要的。
从 0.4.6+ 开始，中继超载信息被加入到中继描述符中，但直到 Tor 0.4.7.1-alpha 之后，才提供底层中继指标的接口：指标接口。
启用 MetricsPort
通过 torrc 配置选项MetricsPort，Tor 提供指标端口的访问。
重要的是要明白， 对 Tor 网络用户来说，公开暴露 Tor MetricsPort 是为危险的，因此该端口默认不启用，而且其访问必须受到访问政策的约束。
所以，在打开这个端口时，请务必小心谨慎，并在调试完毕后把它关闭。
假设你是运行了 Tor 中继的服务器上的唯一用户。
可以在 torrc 文件中添加以下内容来启用指标端口：
MetricsPort 127.0.0.1:9035
MetricsPortPolicy accept 127.0.0.1
然后使用以下命令可轻松获取指标：
# curl http://127.0.0.1:9035/metrics
默认为 Prometheus 格式。
注意： 该服务器上的每个用户都能够访问上述例子中的中继指标。
通常，可通过MetricsPortPolicy 设置严格的访问政策，并考虑使用操作系统防火墙功能进行深度防御。
关于 MetricsPort 和MetricsPortPolicy更详细的解释，请参阅 tor 的 man 页面。
MetricsPort 输出
以下示例为MetricsPort 启用后生成的输出（删去了所有与拥塞控制有关的指标，因为我们仍然需要稳定该接口）：
# HELP tor_relay_connections Total number of opened connections
# TYPE tor_relay_connections gauge
tor_relay_connections{type="OR listener",direction="initiated",state="opened",family="ipv4"} 0
tor_relay_connections{type="OR listener",direction="initiated",state="opened",family="ipv6"} 0
tor_relay_connections{type="OR listener",direction="received",state="opened",family="ipv4"} 0
tor_relay_connections{type="OR listener",direction="received",state="opened",family="ipv6"} 0
tor_relay_connections{type="OR",direction="initiated",state="opened",family="ipv4"} 0
tor_relay_connections{type="OR",direction="initiated",state="opened",family="ipv6"} 0
tor_relay_connections{type="OR",direction="received",state="opened",family="ipv4"} 0
tor_relay_connections{type="OR",direction="received",state="opened",family="ipv6"} 0
tor_relay_connections{type="Exit",direction="initiated",state="opened",family="ipv4"} 0
tor_relay_connections{type="Exit",direction="initiated",state="opened",family="ipv6"} 0
tor_relay_connections{type="Exit",direction="received",state="opened",family="ipv4"} 0
tor_relay_connections{type="Exit",direction="received",state="opened",family="ipv6"} 0
tor_relay_connections{type="Socks listener",direction="initiated",state="opened",family="ipv4"} 0
tor_relay_connections{type="Socks listener",direction="initiated",state="opened",family="ipv6"} 0
tor_relay_connections{type="Socks listener",direction="received",state="opened",family="ipv4"} 0
tor_relay_connections{type="Socks listener",direction="received",state="opened",family="ipv6"} 0
tor_relay_connections{type="Socks",direction="initiated",state="opened",family="ipv4"} 0
tor_relay_connections{type="Socks",direction="initiated",state="opened",family="ipv6"} 0
tor_relay_connections{type="Socks",direction="received",state="opened",family="ipv4"} 0
tor_relay_connections{type="Socks",direction="received",state="opened",family="ipv6"} 0
tor_relay_connections{type="Directory listener",direction="initiated",state="opened",family="ipv4"} 0
tor_relay_connections{type="Directory listener",direction="initiated",state="opened",family="ipv6"} 0
tor_relay_connections{type="Directory listener",direction="received",state="opened",family="ipv4"} 0
tor_relay_connections{type="Directory listener",direction="received",state="opened",family="ipv6"} 0
tor_relay_connections{type="Directory",direction="initiated",state="opened",family="ipv4"} 0
tor_relay_connections{type="Directory",direction="initiated",state="opened",family="ipv6"} 0
tor_relay_connections{type="Directory",direction="received",state="opened",family="ipv4"} 0
tor_relay_connections{type="Directory",direction="received",state="opened",family="ipv6"} 0
tor_relay_connections{type="Control listener",direction="initiated",state="opened",family="ipv4"} 0
tor_relay_connections{type="Control listener",direction="initiated",state="opened",family="ipv6"} 0
tor_relay_connections{type="Control listener",direction="received",state="opened",family="ipv4"} 0
tor_relay_connections{type="Control listener",direction="received",state="opened",family="ipv6"} 0
tor_relay_connections{type="Control",direction="initiated",state="opened",family="ipv4"} 0
tor_relay_connections{type="Control",direction="initiated",state="opened",family="ipv6"} 0
tor_relay_connections{type="Control",direction="received",state="opened",family="ipv4"} 0
tor_relay_connections{type="Control",direction="received",state="opened",family="ipv6"} 0
tor_relay_connections{type="Transparent pf/netfilter listener",direction="initiated",state="opened",family="ipv4"} 0
tor_relay_connections{type="Transparent pf/netfilter listener",direction="initiated",state="opened",family="ipv6"} 0
tor_relay_connections{type="Transparent pf/netfilter listener",direction="received",state="opened",family="ipv4"} 0
tor_relay_connections{type="Transparent pf/netfilter listener",direction="received",state="opened",family="ipv6"} 0
tor_relay_connections{type="Transparent natd listener",direction="initiated",state="opened",family="ipv4"} 0
tor_relay_connections{type="Transparent natd listener",direction="initiated",state="opened",family="ipv6"} 0
tor_relay_connections{type="Transparent natd listener",direction="received",state="opened",family="ipv4"} 0
tor_relay_connections{type="Transparent natd listener",direction="received",state="opened",family="ipv6"} 0
tor_relay_connections{type="DNS listener",direction="initiated",state="opened",family="ipv4"} 0
tor_relay_connections{type="DNS listener",direction="initiated",state="opened",family="ipv6"} 0
tor_relay_connections{type="DNS listener",direction="received",state="opened",family="ipv4"} 0
tor_relay_connections{type="DNS listener",direction="received",state="opened",family="ipv6"} 0
tor_relay_connections{type="Extended OR",direction="initiated",state="opened",family="ipv4"} 0
tor_relay_connections{type="Extended OR",direction="initiated",state="opened",family="ipv6"} 0
tor_relay_connections{type="Extended OR",direction="received",state="opened",family="ipv4"} 0
tor_relay_connections{type="Extended OR",direction="received",state="opened",family="ipv6"} 0
tor_relay_connections{type="Extended OR listener",direction="initiated",state="opened",family="ipv4"} 0
tor_relay_connections{type="Extended OR listener",direction="initiated",state="opened",family="ipv6"} 0
tor_relay_connections{type="Extended OR listener",direction="received",state="opened",family="ipv4"} 0
tor_relay_connections{type="Extended OR listener",direction="received",state="opened",family="ipv6"} 0
tor_relay_connections{type="HTTP tunnel listener",direction="initiated",state="opened",family="ipv4"} 0
tor_relay_connections{type="HTTP tunnel listener",direction="initiated",state="opened",family="ipv6"} 0
tor_relay_connections{type="HTTP tunnel listener",direction="received",state="opened",family="ipv4"} 0
tor_relay_connections{type="HTTP tunnel listener",direction="received",state="opened",family="ipv6"} 0
tor_relay_connections{type="Metrics listener",direction="initiated",state="opened",family="ipv4"} 0
tor_relay_connections{type="Metrics listener",direction="initiated",state="opened",family="ipv6"} 0
tor_relay_connections{type="Metrics listener",direction="received",state="opened",family="ipv4"} 0
tor_relay_connections{type="Metrics listener",direction="received",state="opened",family="ipv6"} 0
tor_relay_connections{type="Metrics",direction="initiated",state="opened",family="ipv4"} 0
tor_relay_connections{type="Metrics",direction="initiated",state="opened",family="ipv6"} 0
tor_relay_connections{type="Metrics",direction="received",state="opened",family="ipv4"} 0
tor_relay_connections{type="Metrics",direction="received",state="opened",family="ipv6"} 0
# HELP tor_relay_connections_total Total number of created/rejected connections
# TYPE tor_relay_connections_total counter
tor_relay_connections_total{type="OR listener",direction="initiated",state="created",family="ipv4"} 0
tor_relay_connections_total{type="OR listener",direction="initiated",state="created",family="ipv6"} 0
tor_relay_connections_total{type="OR listener",direction="received",state="created",family="ipv4"} 0
tor_relay_connections_total{type="OR listener",direction="received",state="created",family="ipv6"} 0
tor_relay_connections_total{type="OR listener",direction="received",state="rejected",family="ipv4"} 0
tor_relay_connections_total{type="OR listener",direction="received",state="rejected",family="ipv6"} 0
tor_relay_connections_total{type="OR",direction="initiated",state="created",family="ipv4"} 0
tor_relay_connections_total{type="OR",direction="initiated",state="created",family="ipv6"} 0
tor_relay_connections_total{type="OR",direction="received",state="created",family="ipv4"} 0
tor_relay_connections_total{type="OR",direction="received",state="created",family="ipv6"} 0
tor_relay_connections_total{type="OR",direction="received",state="rejected",family="ipv4"} 0
tor_relay_connections_total{type="OR",direction="received",state="rejected",family="ipv6"} 0
tor_relay_connections_total{type="Exit",direction="initiated",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Exit",direction="initiated",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Exit",direction="received",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Exit",direction="received",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Exit",direction="received",state="rejected",family="ipv4"} 0
tor_relay_connections_total{type="Exit",direction="received",state="rejected",family="ipv6"} 0
tor_relay_connections_total{type="Socks listener",direction="initiated",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Socks listener",direction="initiated",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Socks listener",direction="received",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Socks listener",direction="received",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Socks listener",direction="received",state="rejected",family="ipv4"} 0
tor_relay_connections_total{type="Socks listener",direction="received",state="rejected",family="ipv6"} 0
tor_relay_connections_total{type="Socks",direction="initiated",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Socks",direction="initiated",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Socks",direction="received",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Socks",direction="received",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Socks",direction="received",state="rejected",family="ipv4"} 0
tor_relay_connections_total{type="Socks",direction="received",state="rejected",family="ipv6"} 0
tor_relay_connections_total{type="Directory listener",direction="initiated",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Directory listener",direction="initiated",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Directory listener",direction="received",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Directory listener",direction="received",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Directory listener",direction="received",state="rejected",family="ipv4"} 0
tor_relay_connections_total{type="Directory listener",direction="received",state="rejected",family="ipv6"} 0
tor_relay_connections_total{type="Directory",direction="initiated",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Directory",direction="initiated",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Directory",direction="received",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Directory",direction="received",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Directory",direction="received",state="rejected",family="ipv4"} 0
tor_relay_connections_total{type="Directory",direction="received",state="rejected",family="ipv6"} 0
tor_relay_connections_total{type="Control listener",direction="initiated",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Control listener",direction="initiated",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Control listener",direction="received",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Control listener",direction="received",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Control listener",direction="received",state="rejected",family="ipv4"} 0
tor_relay_connections_total{type="Control listener",direction="received",state="rejected",family="ipv6"} 0
tor_relay_connections_total{type="Control",direction="initiated",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Control",direction="initiated",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Control",direction="received",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Control",direction="received",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Control",direction="received",state="rejected",family="ipv4"} 0
tor_relay_connections_total{type="Control",direction="received",state="rejected",family="ipv6"} 0
tor_relay_connections_total{type="Transparent pf/netfilter listener",direction="initiated",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Transparent pf/netfilter listener",direction="initiated",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Transparent pf/netfilter listener",direction="received",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Transparent pf/netfilter listener",direction="received",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Transparent pf/netfilter listener",direction="received",state="rejected",family="ipv4"} 0
tor_relay_connections_total{type="Transparent pf/netfilter listener",direction="received",state="rejected",family="ipv6"} 0
tor_relay_connections_total{type="Transparent natd listener",direction="initiated",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Transparent natd listener",direction="initiated",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Transparent natd listener",direction="received",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Transparent natd listener",direction="received",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Transparent natd listener",direction="received",state="rejected",family="ipv4"} 0
tor_relay_connections_total{type="Transparent natd listener",direction="received",state="rejected",family="ipv6"} 0
tor_relay_connections_total{type="DNS listener",direction="initiated",state="created",family="ipv4"} 0
tor_relay_connections_total{type="DNS listener",direction="initiated",state="created",family="ipv6"} 0
tor_relay_connections_total{type="DNS listener",direction="received",state="created",family="ipv4"} 0
tor_relay_connections_total{type="DNS listener",direction="received",state="created",family="ipv6"} 0
tor_relay_connections_total{type="DNS listener",direction="received",state="rejected",family="ipv4"} 0
tor_relay_connections_total{type="DNS listener",direction="received",state="rejected",family="ipv6"} 0
tor_relay_connections_total{type="Extended OR",direction="initiated",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Extended OR",direction="initiated",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Extended OR",direction="received",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Extended OR",direction="received",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Extended OR",direction="received",state="rejected",family="ipv4"} 0
tor_relay_connections_total{type="Extended OR",direction="received",state="rejected",family="ipv6"} 0
tor_relay_connections_total{type="Extended OR listener",direction="initiated",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Extended OR listener",direction="initiated",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Extended OR listener",direction="received",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Extended OR listener",direction="received",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Extended OR listener",direction="received",state="rejected",family="ipv4"} 0
tor_relay_connections_total{type="Extended OR listener",direction="received",state="rejected",family="ipv6"} 0
tor_relay_connections_total{type="HTTP tunnel listener",direction="initiated",state="created",family="ipv4"} 0
tor_relay_connections_total{type="HTTP tunnel listener",direction="initiated",state="created",family="ipv6"} 0
tor_relay_connections_total{type="HTTP tunnel listener",direction="received",state="created",family="ipv4"} 0
tor_relay_connections_total{type="HTTP tunnel listener",direction="received",state="created",family="ipv6"} 0
tor_relay_connections_total{type="HTTP tunnel listener",direction="received",state="rejected",family="ipv4"} 0
tor_relay_connections_total{type="HTTP tunnel listener",direction="received",state="rejected",family="ipv6"} 0
tor_relay_connections_total{type="Metrics listener",direction="initiated",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Metrics listener",direction="initiated",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Metrics listener",direction="received",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Metrics listener",direction="received",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Metrics listener",direction="received",state="rejected",family="ipv4"} 0
tor_relay_connections_total{type="Metrics listener",direction="received",state="rejected",family="ipv6"} 0
tor_relay_connections_total{type="Metrics",direction="initiated",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Metrics",direction="initiated",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Metrics",direction="received",state="created",family="ipv4"} 0
tor_relay_connections_total{type="Metrics",direction="received",state="created",family="ipv6"} 0
tor_relay_connections_total{type="Metrics",direction="received",state="rejected",family="ipv4"} 0
tor_relay_connections_total{type="Metrics",direction="received",state="rejected",family="ipv6"} 0
# HELP tor_relay_flag Relay flags from consensus
# TYPE tor_relay_flag gauge
tor_relay_flag{type="Fast"} 0
tor_relay_flag{type="Exit"} 0
tor_relay_flag{type="Authority"} 0
tor_relay_flag{type="Stable"} 0
tor_relay_flag{type="HSDir"} 0
tor_relay_flag{type="Running"} 0
tor_relay_flag{type="V2Dir"} 0
tor_relay_flag{type="Sybil"} 0
tor_relay_flag{type="Guard"} 0
# HELP tor_relay_circuits_total Total number of circuits
# TYPE tor_relay_circuits_total gauge
tor_relay_circuits_total{state="opened"} 0
# HELP tor_relay_streams_total Total number of streams
# TYPE tor_relay_streams_total counter
tor_relay_streams_total{type="BEGIN"} 0
tor_relay_streams_total{type="BEGIN_DIR"} 0
tor_relay_streams_total{type="RESOLVE"} 0
# HELP tor_relay_traffic_bytes Traffic related counters
# TYPE tor_relay_traffic_bytes counter
tor_relay_traffic_bytes{direction="read"} 0
tor_relay_traffic_bytes{direction="written"} 0
# HELP tor_relay_dos_total Denial of Service defenses related counters
# TYPE tor_relay_dos_total counter
tor_relay_dos_total{type="circuit_rejected"} 0
tor_relay_dos_total{type="circuit_killed_max_cell"} 0
tor_relay_dos_total{type="circuit_killed_max_cell_outq"} 0
tor_relay_dos_total{type="marked_address"} 0
tor_relay_dos_total{type="marked_address_maxq"} 0
tor_relay_dos_total{type="conn_rejected"} 0
tor_relay_dos_total{type="concurrent_conn_rejected"} 0
tor_relay_dos_total{type="single_hop_refused"} 0
tor_relay_dos_total{type="introduce2_rejected"} 0
# HELP tor_relay_load_onionskins_total Total number of onionskins handled
# TYPE tor_relay_load_onionskins_total counter
tor_relay_load_onionskins_total{type="tap",action="processed"} 0
tor_relay_load_onionskins_total{type="tap",action="dropped"} 0
tor_relay_load_onionskins_total{type="fast",action="processed"} 0
tor_relay_load_onionskins_total{type="fast",action="dropped"} 0
tor_relay_load_onionskins_total{type="ntor",action="processed"} 0
tor_relay_load_onionskins_total{type="ntor",action="dropped"} 0
tor_relay_load_onionskins_total{type="ntor_v3",action="processed"} 0
tor_relay_load_onionskins_total{type="ntor_v3",action="dropped"} 0
# HELP tor_relay_exit_dns_query_total Total number of DNS queries done by this relay
# TYPE tor_relay_exit_dns_query_total counter
tor_relay_exit_dns_query_total 0
# HELP tor_relay_exit_dns_error_total Total number of DNS errors encountered by this relay
# TYPE tor_relay_exit_dns_error_total counter
tor_relay_exit_dns_error_total{reason="success"} 0
tor_relay_exit_dns_error_total{reason="format"} 0
tor_relay_exit_dns_error_total{reason="serverfailed"} 0
tor_relay_exit_dns_error_total{reason="notexist"} 0
tor_relay_exit_dns_error_total{reason="notimpl"} 0
tor_relay_exit_dns_error_total{reason="refused"} 0
tor_relay_exit_dns_error_total{reason="truncated"} 0
tor_relay_exit_dns_error_total{reason="unknown"} 0
tor_relay_exit_dns_error_total{reason="tor_timeout"} 0
tor_relay_exit_dns_error_total{reason="shutdown"} 0
tor_relay_exit_dns_error_total{reason="cancel"} 0
tor_relay_exit_dns_error_total{reason="nodata"} 0
# HELP tor_relay_load_oom_bytes_total Total number of bytes the OOM has freed by subsystem
# TYPE tor_relay_load_oom_bytes_total counter
tor_relay_load_oom_bytes_total{subsys="cell"} 0
tor_relay_load_oom_bytes_total{subsys="dns"} 0
tor_relay_load_oom_bytes_total{subsys="geoip"} 0
tor_relay_load_oom_bytes_total{subsys="hsdir"} 0
# HELP tor_relay_load_socket_total Total number of sockets
# TYPE tor_relay_load_socket_total gauge
tor_relay_load_socket_total{state="opened"} 0
tor_relay_load_socket_total 0
# HELP tor_relay_load_tcp_exhaustion_total Total number of times we ran out of TCP ports
# TYPE tor_relay_load_tcp_exhaustion_total counter
tor_relay_load_tcp_exhaustion_total 0
# HELP tor_relay_load_global_rate_limit_reached_total Total number of global connection bucket limit reached
# TYPE tor_relay_load_global_rate_limit_reached_total counter
tor_relay_load_global_rate_limit_reached_total{side="read"} 0
tor_relay_load_global_rate_limit_reached_total{side="write"} 0
下面解释其中一些行代表的意思：
tor_relay_load_onionskins_total{type="ntor",action="dropped"} 0
当中继开始出现“dropped”时，通常是 CPU 或内存出现问题。
除了 在处理 “洋葱皮” 进程时，Tor 是单线程的。
在每个线路著名的“洋葱层”上，需要进行的加密工作就是“洋葱皮”。
当 Tor 处理这些层时，我们使用线程池，并将所有工作外包到该线程池。
可能出现，由于内存或 CPU 的压力，该线程池开始丢弃工作，进而触发一个超载状态。
如果服务器满负载运行，很可能触发它。
tor_relay_exit_dns_error_total{...}
“*_dns_error_total” 领域的任何计数器（成功查询的除外）都表明可能存在 DNS 相关的问题。
然而，我们在 0.4.7 的发布周期中意识到，DNS 错误的噪音太大，且包含太多的假阳性，不可用于超载报告。
因此，从 0.4.6.9 和 0.4.7.4-alpha 开始，我们不再将其用于此目的。然而，为了便于中继操作员了解中继发生了什么，仍然保留了 DNS 指标。
DNS 超时问题和错误只适用于出口节点。
tor_relay_load_oom_bytes_total{...}
内存不足调用表示这是内存的问题。
该中继需要更多的 RAM 或者它正在泄露内存。
如果 tor 出现内存泄露，请通过 Tor gitLab 或发送邮件至tor-relays 邮件列表报告这个问题。
Tor 自带 OOM 处理程序。当达到 tor 认为的可使用内存的 75% 时，将调用该处理程序。
Thus, let's say tor thinks it can use 2GB in total then at 1.5GB of memory usage, it will start freeing memory.
这视为超载状态。
To estimate the amount of memory it has available, when tor starts, it will use MaxMemInQueues or, if not set, will look at the total RAM available on the system and apply this algorithm:
if RAM >= 8GB {
memory = RAM * 40%
} else {
memory = RAM * 75%
}
/* Capped. */
memory = min(memory, 8GB) -> [8GB on 64bit and 2GB on 32bit)
/* Minimum value. */
memory = max(250MB, memory)
为了避免过载状态，我们建议在 64 位上运行内存 2GB 以上的中继。
建议 4GB，当然，也可以增加更多的内存。
Note: If you are running a powerful server with lots of RAM then you might end up in an overloaded state due to the default queue size limit of 8GB even though you still have plenty of RAM unused. Add an appropriate MaxMemInQueues entry to your torrc configuration in that case.
可能有人会注意到， Tor 可能被操作系统的 OOM 处理程序自身调用。
因为 tor 在启动时占用了系统的总内存，如果整个系统还有许多其他应用程序也在使用内存运行，那么最终占用太多内存。
在这种情况下，操作系统可能会使 Tor 的内存不足，而 Tor 甚至都没有注意到内存压力。
tor_relay_load_socket_total
如果打开的 socket 端口数量接近或等于可用的总数，那么这就表明，中继 socket 端口快要用尽了。
解决方法是增加 Tor 进程的ulimit -n 。
tor_relay_load_tcp_exhaustion_total
这几行表示中继的 TCP 端口快要用尽了。
尝试按照上述方法调整sysctl。
tor_relay_load_global_rate_limit_reached_total
如果在短期内，这个计数器数值出现明显递增，那么这个中继发生了拥塞。
它很可能用作大型洋葱服务的守卫节点，或者用于在网络上进行 DDoS。
如果中继仍超载，而且不知道为什么，请联系 network-report@torproject.org。
可以使用 network-report OpenPGP 密钥来加密邮件。