Great question! Let’s break this down step by step—whether you’re new to z/OS health checks or looking to leverage Unix System Services (USS), I’ve got you covered.

First: Start with z/OS’s Native Health Checker Framework #

z/OS includes a built-in Health Checker (HCHECKER) framework that’s the gold standard for system health checks. It integrates seamlessly with z/OS’s logging, automation, and monitoring tools, so it’s the best place to start. Here’s how to dive in:

Step 1: Define Your Check’s Purpose #

First, narrow down what you want to validate. Common use cases include:

• Checking accessibility of critical datasets (like SYS1.PARMLIB)
• Verifying system parameter values (e.g., MAXUSER settings)
• Monitoring resource thresholds (CPU, storage, or USS file system usage)
• Ensuring critical jobs are running (e.g., batch schedulers, backup processes)

Step 2: Choose a Development Language #

Most z/OS health checks are written in REXX—it’s lightweight, easy to learn, and has direct access to z/OS system services. You can also use Assembler (for high-performance checks) or Java (if you need to leverage modern libraries).

Step 3: Example REXX Health Check #

Here’s a simple REXX script to verify a critical dataset is accessible:

/* REXX: Check accessibility of SYS1.PARMLIB */
Address SYSCALL "BPXWDYN 'ALLOC FI(CRITDS) DA(''SYS1.PARMLIB'') SHR REUSE'"

If RC <> 0 Then Do
  Say "ERROR: Critical dataset SYS1.PARMLIB is unavailable. RC="RC
  Exit 8 /* Return error code to HCHECKER */
End
Else Do
  Say "SUCCESS: SYS1.PARMLIB is accessible."
  Exit 0 /* Return success code */
End

Address SYSCALL "BPXWDYN 'FREE FI(CRITDS)'"

Step 4: Register Your Check with HCHECKER #

To make your check run automatically, add it to the HCHECKER configuration in SYS1.PARMLIB(HZSPRMxx):

CHECK(USER.CRIT_DATASET_CHECK,
      "Validate accessibility of SYS1.PARMLIB",
      REXX(USER.CRIT_DATASET.REXX), /* Point to your REXX member */
      INTERVAL(60), /* Run every 60 minutes */
      SEVERITY(WARNING)) /* Set severity level */

Can You Write Health Checks in USS? #

Absolutely! USS is a fully integrated part of z/OS, so you can use Unix-style tools and scripting languages to build health checks. This is perfect if you’re more comfortable with bash, Python, or Perl.

Benefits of USS Health Checks #

• Familiar syntax for Unix developers
• Access to USS tools like df, ps, grep, and awk for quick analysis
• Ability to call z/OS system services via USS APIs (e.g., accessing MVS datasets from bash)

Example Bash Health Check (USS File System Usage) #

Here’s a bash script to alert if any USS file system exceeds an 85% usage threshold:

#!/bin/sh
# USS Health Check: Monitor file system usage
THRESHOLD=85

# Check each file system
df -P | awk -v threshold="$THRESHOLD" 'NR>1 {
  usage = substr($5, 1, length($5)-1)
  if (usage > threshold) {
    printf "WARNING: File system %s is at %d%% usage (threshold: %d%%)\n", $6, usage, threshold
    exit 1
  }
}'

# Return exit code based on check result
if [ $? -eq 1 ]; then
  exit 1 # Trigger alert in monitoring tools
else
  echo "SUCCESS: All USS file systems are within usage limits."
  exit 0
fi

Running USS Checks Automatically #

• USS Cron: Schedule the script to run periodically using crontab:

  0 */1 * * * /u/yourid/scripts/check_filesystems.sh >> /u/yourid/logs/health_checks.log 2>&1
  

• Integrate with HCHECKER: Call your USS script from a REXX check to leverage z/OS’s native monitoring:

  Address BPXBATCH "SH /u/yourid/scripts/check_filesystems.sh"
  If RC <> 0 Then Exit RC
  Else Exit 0
  

Pro Tips for Success #

• Start small: Build simple checks first (e.g., dataset existence) before moving to complex performance monitoring.
• Test rigorously: Validate your checks in a test z/OS environment to avoid false positives/negatives in production.
• Automate alerts: Integrate check results with z/OS automation tools (like AutoOPERATOR) or set up email/SMS alerts for critical failures.
• Leverage existing tools: Use z/OS commands like D OMVS (USS status) or D SMS (storage status) as part of your checks.

内容的提问来源于stack exchange，提问作者Jade Steffen