Linux NUMA Imbalance
Linux NUMA memory allocation is imbalanced when processes are not bound correctly.
Category archive
Linux System fixes
Published troubleshooting guides for linux system issues.
Linux IRQ Balancing Suboptimal
Linux IRQ balancing does not distribute load when service is disabled.
Linux Transparent Huge Pages Latency
Linux THP causes latency spikes when defrag is set to always.
Linux HugeTLB Pages Not Allocated
Linux HugeTLB pages are not allocated when vm.nr_hugepages is not set.
Linux Swap Thrashing
Linux system thrashes on swap when working set exceeds physical memory.
Linux fstrim Not Discarding
Linux fstrim does not discard blocks when SSD does not support TRIM.
Linux timerd Unit Not Triggering
Linux systemd timers do not trigger when OnCalendar expression is invalid.
Linux anacron Missed Jobs
Linux anacron does not run missed jobs when system is off during scheduled time.
Linux Cron Job Not Running
Linux cron jobs do not run when crontab syntax is invalid or MAILTO causes issues.
Linux rsyslog Remote Forwarding Broken
Linux rsyslog does not forward logs when TCP connection to aggregator fails.
Linux Journalctl Corrupted
Linux systemd journal is corrupted after unclean shutdown.
Linux Audit Log Disk Full
Linux audit subsystem stops logging when partition is full.
Linux Namespaces PID Leak
Linux PID namespace exhaustion prevents new process creation.
Linux cgroup Memory Leak
Linux cgroup memory usage grows unbounded when limits are not configured.
Linux Ulimit Too Low
Linux processes hit resource limits when ulimit is set too conservatively.
Linux tuned Profile Not Applying
Linux tuned does not apply profiles when service is not running.
Linux thermald Throttling
Linux thermal daemon throttles CPU when temperature exceeds trip points.
Linux CPU Governor Performance
Linux CPU frequency scaling is stuck in powersave when governor is wrong.
Linux PCIe Passthrough VFIO Bind Failed
Linux VFIO cannot bind device when IOMMU is not enabled in kernel.
Linux KVM Nested Virt Not Working
Linux KVM nested virtualization fails when module parameter is disabled.
Linux Libvirt Network Not Forwarding
Linux libvirt NAT networking fails when iptables rules are flushed.
Linux Docker Storage Driver Wrong
Linux Docker uses inefficient storage driver when overlay2 is not available.
Linux Winbind Domain Trust Broken
Linux Winbind cannot authenticate when Active Directory trust is broken.
Linux SSSD LDAP Offline
Linux SSSD caches credentials when LDAP server is unreachable.
Linux PAM Authentication Failed
Linux PAM authentication fails when module configuration is incorrect.
Linux Sudoers Syntax Error
Linux sudo fails when sudoers file has syntax errors.
Linux SSHD Max Startups Reached
Linux SSHD rejects connections when MaxStartups limit is exceeded.
Linux SSHD Permission Denied
Linux SSH authentication fails when file permissions are too open.
Linux networkd resolv.conf Wrong
Linux systemd-networkd does not update resolv.conf when DNS is misconfigured.
Linux Netplan Apply Failed
Linux netplan configuration fails when YAML syntax is invalid.
Linux Network Manager Connection Lost
Linux NetworkManager connections drop when profiles are misconfigured.
Linux nftables Rules Not Persistent
Linux nftables rules are lost after reboot when not saved properly.
Linux iptables Masquerade Not Working
Linux NAT masquerade fails when IP forwarding is disabled.
Linux Firewalld Zones Wrong
Linux firewalld blocks traffic when interface is assigned to wrong zone.
Linux AppArmor Profile Complaining
Linux AppArmor logs denials when profile does not permit the operation.
Linux SELinux Denying Access
Linux SELinux denies operations when contexts or booleans are misconfigured.
Linux Btrfs Scrub Errors
Linux Btrfs scrub reports checksum errors indicating data corruption.
Linux ZFS Pool Faulted
Linux ZFS pools are faulted when vdev members are unavailable.
Linux MDADM RAID Degraded
Linux software RAID is degraded when member disks fail or are disconnected.
Linux LVM Volume Group Not Found
Linux LVM volume groups are not found when physical volumes are missing.
Linux GRUB Bootloader Corrupted
Linux GRUB fails to load when stage1 or stage2 is corrupted.
Linux Kernel Panic After Boot
Linux kernel panics during boot when root filesystem cannot be mounted.
Linux NTP Time Drift
Linux system clock drifts when NTP daemon cannot reach time servers.
Linux Syslog Not Rotating
Linux logrotate fails when postrotate scripts return errors.
Linux Zombie Processes Accumulating
Linux zombie processes accumulate when parent does not call wait().
Linux Inode Exhaustion
Linux cannot create files when all inodes are consumed despite free disk space.
Linux Filesystem Read Only
Linux remounts filesystem read-only when disk errors or corruption is detected.
Linux OOM Killer Terminating Processes
Linux OOM killer terminates processes when memory is exhausted and no swap is available.
Linux Disk IO Wait High
Linux high IO wait indicates storage bottleneck from slow disks or saturation.
Linux Systemd Unit Failed
Linux systemd services fail when ExecStart command is invalid or dependencies are not met.