JAVA J2EE 4 U

 #!/bin/bash

SGA_GB=128

SGA_MB=$((SGA_GB * 1024))

SGA_KB=$((SGA_MB * 1024))

echo "🔍 Oracle SGA Feasibility + Recommendation (Target: ${SGA_GB} GB)"

echo "-------------------------------------------------------------"

# Get system memory

TOTAL_MEM_KB=$(grep MemTotal /proc/meminfo | awk '{print $2}')

TOTAL_MEM_GB=$((TOTAL_MEM_KB / 1024 / 1024))

echo "🧠 Total Physical Memory: ${TOTAL_MEM_GB} GB"

# Get HugePages info

HP_SIZE_KB=$(grep Hugepagesize /proc/meminfo | awk '{print $2}')

HP_TOTAL=$(grep HugePages_Total /proc/meminfo | awk '{print $2}')

HP_FREE=$(grep HugePages_Free /proc/meminfo | awk '{print $2}')

HP_RSVD=$(grep HugePages_Rsvd /proc/meminfo | awk '{print $2}')

HP_USED=$((HP_TOTAL - HP_FREE))

# Required HugePages

REQUIRED_HUGEPAGES=$((SGA_KB / HP_SIZE_KB))

HP_TOTAL_KB=$((HP_TOTAL * HP_SIZE_KB))

HP_FREE_KB=$((HP_FREE * HP_SIZE_KB))

# Print HugePages summary

echo "📦 HugePage Size: $((HP_SIZE_KB / 1024)) MB"

echo "📦 HugePages Configured: ${HP_TOTAL} (${HP_TOTAL_KB} KB)"

echo "📦 HugePages Free: ${HP_FREE} (${HP_FREE_KB} KB)"

echo "📐 Required HugePages for ${SGA_GB} GB SGA: ${REQUIRED_HUGEPAGES}"

echo "-------------------------------------------------------------"

# Evaluation

if [ "$TOTAL_MEM_KB" -lt "$((SGA_KB + 10485760))" ]; then

  echo "❌ ERROR: Not enough physical memory for ${SGA_GB} GB SGA + OS overhead."

  exit 1

fi

if [ "$HP_TOTAL" -lt "$REQUIRED_HUGEPAGES" ]; then

  echo "❌ ERROR: HugePages configured are less than required."

  echo "➡️  You need at least $REQUIRED_HUGEPAGES HugePages."

  echo -e "\n🛠️ Suggested /etc/sysctl.conf settings:"

  echo "vm.nr_hugepages = ${REQUIRED_HUGEPAGES}"

  echo "kernel.shmmax = $((SGA_GB * 1024 * 1024 * 1024))"

  echo "kernel.shmall = $((SGA_KB / 4))    # (SGA / 4KB)"

  echo -e "\n🛠️ Suggested /etc/security/limits.conf for oracle:"

  echo "oracle soft memlock ${SGA_KB}"

  echo "oracle hard memlock ${SGA_KB}"

  echo "oracle soft nofile 65536"

  echo "oracle hard nofile 65536"

  echo "oracle soft nproc 16384"

  echo "oracle hard nproc 16384"

  echo -e "\n⚠️ Don't forget to disable MEMORY_TARGET and MEMORY_MAX_TARGET in Oracle:"

  echo "ALTER SYSTEM SET MEMORY_TARGET=0 SCOPE=SPFILE;"

  echo "ALTER SYSTEM SET MEMORY_MAX_TARGET=0 SCOPE=SPFILE;"

  echo "ALTER SYSTEM SET SGA_MAX_SIZE=${SGA_GB}G SCOPE=SPFILE;"

  echo "ALTER SYSTEM SET SGA_TARGET=${SGA_GB}G SCOPE=SPFILE;"

  echo "➡️  Then restart the DB."

  exit 1

fi

if [ "$HP_FREE" -lt "$REQUIRED_HUGEPAGES" ]; then

  echo "⚠️ WARNING: Not enough HugePages FREE at the moment."

  echo "➡️  You may need to stop other Oracle instances or reboot the system."

  exit 1

fi

echo "✅ YES: Server is READY for ${SGA_GB} GB SGA allocation using HugePages!"

exit 0