Understanding HP-UX in Enterprise Context

Unique Characteristics of HP-UX

HP-UX is tailored for PA-RISC and Itanium architectures with unique features like Serviceguard clustering, Online JFS (VxFS), and LVM enhancements. It also includes tools like glance, top, and kctune for low-level system introspection.

Deployment Landscape

  • Legacy Oracle or SAP deployments
  • High-availability clusters via Serviceguard
  • Critical workloads on Superdome or Integrity servers

Common Yet Complex Issues

1. Memory Leaks in Long-Running Applications

Applications may gradually consume kernel memory pools (especially kcdata or msgmni), leading to failures in process forking or IPC usage. Standard tools rarely expose this directly.

2. Hung Processes and Zombie States

Processes get stuck due to blocked I/O (especially on NFS or Fibre Channel devices) or unhandled signals. ps -ef -o state may reveal "Z" or "D" state processes not cleared by init.

3. LVM and VxFS Performance Bottlenecks

Slow disk I/O might stem from fragmented logical volumes, misaligned extents, or VxFS tuning limits. Applications show delayed responses despite normal CPU load.

4. Network Interface Failures Under Load

NIC drivers (e.g., lan0, igelan) may silently drop packets under high traffic or link negotiation failures. Tools like lanadmin and nwmgr expose interface counters for dropped or deferred packets.

5. Kernel Parameter Misconfigurations

Improper settings for semaphores, file descriptors, or TCP buffers cause subtle errors or throughput degradation. These are usually set via kctune and often misunderstood.

Diagnostics and Advanced Tools

Memory Analysis

Use kmeminfo or sar -r to identify leaking pools. For user-space tracking, leverage gdb with debug symbols or use third-party tools like Caliper.

kmeminfo | grep -i usage
sar -r 5 5

Process State Inspection

Track down zombie or blocked processes using:

ps -ef -o pid,ppid,state,comm | grep -E "[DZ]"
parstatus -v # For process affinity or stuck threads

File System and LVM Performance

Analyze disk response and I/O queue depths:

vxstat -g rootdg -f
iostat -xtn 5 5

Network Layer Debugging

Check link status, packet drops, and negotiation using:

nwmgr -l
lanadmin -x 0
netstat -s

Kernel Tuning and Runtime Validation

List tunables and runtime values:

kctune
kctune maxdsiz_64bit
kctune nproc

Step-by-Step Remediation

Step 1: Isolate Fault Domain

Begin with glance or top to identify bottlenecked resources—CPU, memory, I/O, or network. Correlate with app logs and syslog.

Step 2: Collect Kernel Statistics

Use sar or vmstat to trend system stats over time. Set cron jobs for 5-minute interval captures.

Step 3: Validate Kernel Tunables

Compare current settings with vendor recommendations for your workload. Pay attention to values like max_thread_proc, maxfiles, nflocks.

Step 4: Investigate Disk/Volume Issues

Check for logical volume fragmentation or filesystem overhead:

bdf -i
lvdisplay -v /dev/vg00/lvol1

Step 5: Restart or Patch Faulty Services

If hung processes are found, ensure signal delivery works. If not, prepare for manual kill or patch the affected service binary.

Architectural and Long-Term Solutions

Cluster Health Validation

Use cmviewcl and cmquerycl to validate heartbeat stability and failover nodes in Serviceguard clusters.

Audit I/O Workload Alignment

Use lvmstat and filesystem benchmarks to align LUN stripes, volume extents, and application read/write patterns.

Kernel Hardening

Apply kctune profiles for target roles (e.g., DB servers, app nodes) and isolate critical threads using psrset or mcs policies.

Logging and Alerting Modernization

Integrate legacy HP-UX logs with modern SIEMs via syslog forwarding agents. Regularly rotate and compress logs using logadm or cron scripts.

Plan for OS Modernization

HP-UX is end-of-life on most hardware. Begin workload profiling and port planning to Linux (e.g., RHEL) or Solaris if long-term support is needed.

Conclusion

Troubleshooting HP-UX systems in enterprise environments requires low-level system knowledge and careful tuning. By leveraging tools like glance, kctune, and vxstat, administrators can isolate performance issues stemming from memory leaks, I/O stalls, and kernel bottlenecks. Structured diagnostics, combined with configuration hardening and proactive system monitoring, will ensure legacy HP-UX environments remain stable until full migration paths are in place.

FAQs

1. How can I identify a memory leak on HP-UX?

Use kmeminfo for kernel leaks and gdb or Caliper for user-space analysis. Look for growing resident sets or unfreed IPC resources.

2. What causes zombie processes on HP-UX?

Usually, parent processes fail to reap children due to signal handling issues. These persist until the parent exits or is manually restarted.

3. How do I safely change kernel parameters?

Use kctune with caution and validate changes using kcmodule if they affect core modules. Always document current values before updates.

4. Can HP-UX run modern software stacks?

Only partially. Modern runtimes like Python 3, Docker, or Kubernetes are largely unsupported. Legacy Java or Oracle versions may still work.

5. Is there a migration path from HP-UX?

Yes. Common targets include RHEL, AIX, or Solaris. Begin by profiling application dependencies, kernel calls, and data access patterns.