我自行托管的论坛 (https://intfiction.org/) 在过去几周开始变得非常缓慢，并且频繁出现 502 和 503 错误。
我使用的是稳定分支，版本为 2026.1.5。
在此搜索这些错误并未发现任何可能的原因：
- 论坛构建和启动正常
- 服务器似乎有足够的容量（13.5GB 磁盘空间可用，1.6/1.9G 内存，1.7/2.2G 交换空间）
检查 htop，负载平均值确实看起来很高：1.67, 1.55, 3.12。此进程有时使用超过 40% 的 CPU：unicorn worker[0] -E production -c config/unicorn.conf.rb。
在论坛日志中，我看到大量如下错误：
Job exception: execution expired
net-smtp-0.5.1/lib/net/smtp.rb:663:in 'TCPSocket#initialize'
net-smtp-0.5.1/lib/net/smtp.rb:663:in 'IO.open'
net-smtp-0.5.1/lib/net/smtp.rb:663:in 'Net::SMTP#tcp_socket'
net-smtp-0.5.1/lib/net/smtp.rb:672:in 'block in Net::SMTP#do_start'
timeout-0.5.0/lib/timeout.rb:222:in 'block in Timeout.timeout'
timeout-0.5.0/lib/timeout.rb:229:in 'Timeout.timeout'
net-smtp-0.5.1/lib/net/smtp.rb:671:in 'Net::SMTP#do_start'
net-smtp-0.5.1/lib/net/smtp.rb:642:in 'Net::SMTP#start'
mail-2.9.0/lib/mail/network/delivery_methods/smtp.rb:154:in 'Mail::SMTP#start_smtp_session'
mail-2.9.0/lib/mail/network/delivery_methods/smtp.rb:108:in 'Mail::SMTP#deliver!'
mail-2.9.0/lib/mail/message.rb:269:in 'Mail::Message#deliver!'
/usr/local/lib/ruby/3.4.0/delegate.rb:87:in 'Delegator#method_missing'
/var/www/discourse/lib/email/sender.rb:296:in 'Email::Sender#send'
/var/www/discourse/lib/email/processor.rb:151:in 'Email::Processor#handle_failure'
/var/www/discourse/lib/email/processor.rb:31:in 'Email::Processor#process!'
/var/www/discourse/lib/email/processor.rb:13:in 'Email::Processor.process!'
/var/www/discourse/app/jobs/regular/process_email.rb:8:in 'Jobs::ProcessEmail#execute'
/var/www/discourse/app/jobs/base.rb:318:in 'block (2 levels) in Jobs::Base#perform'
rails_multisite-7.0.0/lib/rails_multisite/connection_management/null_instance.rb:49:in 'RailsMultisite::ConnectionManagement::NullInstance#with_connection'
rails_multisite-7.0.0/lib/rails_multisite/connection_management.rb:17:in 'RailsMultisite::ConnectionManagement.with_connection'
/var/www/discourse/app/jobs/base.rb:305:in 'block in Jobs::Base#perform'
/var/www/discourse/app/jobs/base.rb:301:in 'Array#each'
/var/www/discourse/app/jobs/base.rb:301:in 'Jobs::Base#perform'
sidekiq-7.3.9/lib/sidekiq/processor.rb:220:in 'Sidekiq::Processor#execute_job'
sidekiq-7.3.9/lib/sidekiq/processor.rb:185:in 'block (4 levels) in Sidekiq::Processor#process'
sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:180:in 'Sidekiq::Middleware::Chain#traverse'
sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:183:in 'block in Sidekiq::Middleware::Chain#traverse'
/var/www/discourse/lib/sidekiq/suppress_user_email_errors.rb:6:in 'Sidekiq::SuppressUserEmailErrors#call'
sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:182:in 'Sidekiq::Middleware::Chain#traverse'
sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:183:in 'block in Sidekiq::Middleware::Chain#traverse'
/var/www/discourse/lib/sidekiq/discourse_event.rb:6:in 'Sidekiq::DiscourseEvent#call'
sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:182:in 'Sidekiq::Middleware::Chain#traverse'
sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:183:in 'block in Sidekiq::Middleware::Chain#traverse'
/var/www/discourse/lib/sidekiq/pausable.rb:131:in 'Sidekiq::Pausable#call'
sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:182:in 'Sidekiq::Middleware::Chain#traverse'
sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:183:in 'block in Sidekiq::Middleware::Chain#traverse'
sidekiq-7.3.9/lib/sidekiq/job/interrupt_handler.rb:9:in 'Sidekiq::Job::InterruptHandler#call'
sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:182:in 'Sidekiq::Middleware::Chain#traverse'
sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:183:in 'block in Sidekiq::Middleware::Chain#traverse'
sidekiq-7.3.9/lib/sidekiq/metrics/tracking.rb:26:in 'Sidekiq::Metrics::ExecutionTracker#track'
sidekiq-7.3.9/lib/sidekiq/metrics/tracking.rb:134:in 'Sidekiq::Metrics::Middleware#call'
sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:182:in 'Sidekiq::Middleware::Chain#traverse'
sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:173:in 'Sidekiq::Middleware::Chain#invoke'
sidekiq-7.3.9/lib/sidekiq/processor.rb:184:in 'block (3 levels) in Sidekiq::Processor#process'
sidekiq-7.3.9/lib/sidekiq/processor.rb:145:in 'block (6 levels) in Sidekiq::Processor#dispatch'
sidekiq-7.3.9/lib/sidekiq/job_retry.rb:118:in 'Sidekiq::JobRetry#local'
sidekiq-7.3.9/lib/sidekiq/processor.rb:144:in 'block (5 levels) in Sidekiq::Processor#dispatch'
sidekiq-7.3.9/lib/sidekiq/config.rb:39:in 'block in <class:Config>'
sidekiq-7.3.9/lib/sidekiq/processor.rb:139:in 'block (4 levels) in Sidekiq::Processor#dispatch'
sidekiq-7.3.9/lib/sidekiq/processor.rb:281:in 'Sidekiq::Processor#stats'
sidekiq-7.3.9/lib/sidekiq/processor.rb:134:in 'block (3 levels) in Sidekiq::Processor#dispatch'
sidekiq-7.3.9/lib/sidekiq/job_logger.rb:15:in 'Sidekiq::JobLogger#call'
sidekiq-7.3.9/lib/sidekiq/processor.rb:133:in 'block (2 levels) in Sidekiq::Processor#dispatch'
sidekiq-7.3.9/lib/sidekiq/job_retry.rb:85:in 'Sidekiq::JobRetry#global'
sidekiq-7.3.9/lib/sidekiq/processor.rb:132:in 'block in Sidekiq::Processor#dispatch'
sidekiq-7.3.9/lib/sidekiq/job_logger.rb:40:in 'Sidekiq::JobLogger#prepare'
sidekiq-7.3.9/lib/sidekiq/processor.rb:131:in 'Sidekiq::Processor#dispatch'
sidekiq-7.3.9/lib/sidekiq/processor.rb:183:in 'block (2 levels) in Sidekiq::Processor#process'
sidekiq-7.3.9/lib/sidekiq/processor.rb:182:in 'Thread.handle_interrupt'
sidekiq-7.3.9/lib/sidekiq/processor.rb:182:in 'block in Sidekiq::Processor#process'
sidekiq-7.3.9/lib/sidekiq/processor.rb:181:in 'Thread.handle_interrupt'
sidekiq-7.3.9/lib/sidekiq/processor.rb:181:in 'Sidekiq::Processor#process'
sidekiq-7.3.9/lib/sidekiq/processor.rb:86:in 'Sidekiq::Processor#process_one'
sidekiq-7.3.9/lib/sidekiq/processor.rb:76:in 'Sidekiq::Processor#run'
sidekiq-7.3.9/lib/sidekiq/component.rb:10:in 'Sidekiq::Component#watchdog'
sidekiq-7.3.9/lib/sidekiq/component.rb:19:in 'block in Sidekiq::Component#safe_thread'
我还看到许多关于 Redis 的消息：
Job exception: Connection timed out - user specified timeout: 1.0s (redis://localhost:6379)
您的 Redis 网络连接性能极差。
最近 RTT 读数为 [403941, 62224, 151840, 1536008, 3440226]，理想情况下应 < 1000。
确保 Redis 运行在同一 AZ 中
但我不知道这些是显示 Redis 是原因还是只是症状。
我刚刚运行了 ./launcher rebuild app，情况并没有好转。有什么关于如何诊断此服务器上出现问题的想法吗？
