EC2 OS/Kernel Symptom Diagnostic Troubleshooter (Part 1)
Use the interactive troubleshooter below to identify your EC2 OS/kernel symptom, review the raw evidence, understand the root cause, and apply the recommended fix.
🚨 Step 1: What specific error symptom are you experiencing?
Please click the most accurate description:
Quick Reference Table
| # | Scenario | Key Error Signal | Root Cause | The Fix |
|---|---|---|---|---|
| 1 | I/O operation timeout on NVMe EBS volumes causing the filesystem to be remounted as read-only | Numerical result out of range error when attempting to write to /sys/module/nvme_core/parameters/io_timeout | I/O latency exceeds the default 30-second timeout parameter, causing the Linux NVMe driver to fail the I/O and return an error to the filesystem. | Add nvme_core.io_timeout=4294967295 as a boot parameter. |
| 2 | Increased processor reaction latency and delays in servicing network packet interrupts | sudo turbostat stress -c 2 -t 10 showing cores in deeper sleep states like %c6 | Sleeping cores assigned to handle network packet interrupts take time to wake back up and perform work. | Edit /etc/default/grub to add intel_idle.max_cstate=1 processor.max_cstate=1 to GRUB_CMDLINE_LINUX_DEFAULT, then run sudo grub2-mkconfig -o /boot/grub2/grub.cfg and sudo reboot. |
| 3 | Processor speed variability impacting workloads that require consistent baseline performance | sudo turbostat stress -c 2 -t 10 showing CPU frequencies fluctuating due to Turbo Boost | The default P-state configuration allows Turbo Boost to increase core frequency based on available thermal headroom, creating variable performance. | sudo sh -c "echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo" |
| 4 | Suboptimal I/O request handling and performance on solid state devices | cat /sys/block/nvme0n1/queue/scheduler | An invasive I/O scheduler is configured, whereas for solid state devices and virtualized environments, sequential and random access do not differ significantly. | echo cfq|deadline|noop > /sys/block/nvme0n1/queue/scheduler |