Filesystem testing is a critical process when migrating between storage systems. The core aspects to validate include:

• Data integrity verification
• Performance benchmarking
• Concurrency handling
• Failure recovery
• Permission and ACL validation

For Linux-based systems, consider these powerful testing utilities:

# Stress testing with fsstress
./fsstress -d /mnt/test -n 1000 -p 50 -v

# I/O performance measurement
fio --filename=/mnt/test/testfile --size=1G --rw=randrw --bs=4k --direct=1 --ioengine=libaio --runtime=60 --name=testjob

# Filesystem consistency check
xfs_repair -n /dev/sdX

When moving from ext3 to EFS, pay special attention to:

# Test symbolic link preservation
ln -s source.txt link.txt
rsync -avz /source/path/ user@remote:/efs/mount/

# Verify hard link counts
find /mnt/efs -type f -links +1 -exec ls -li {} \;

# Validate extended attributes
getfattr -d -m - /mnt/efs/important_file

Consider implementing a Python-based test harness:

import unittest
import os
import subprocess

class TestEFSMigration(unittest.TestCase):
    def setUp(self):
        self.test_dir = "/mnt/efs/test_area"
        os.makedirs(self.test_dir, exist_ok=True)
        
    def test_large_file_operations(self):
        test_file = os.path.join(self.test_dir, "large.bin")
        with open(test_file, 'wb') as f:
            f.write(os.urandom(1024*1024*100))  # 100MB file
        
        md5_original = subprocess.check_output(['md5sum', test_file])
        os.rename(test_file, test_file + '.renamed')
        md5_renamed = subprocess.check_output(['md5sum', test_file + '.renamed'])
        self.assertEqual(md5_original, md5_renamed)
        
if __name__ == '__main__':
    unittest.main()

Create a comparative benchmark script:

#!/bin/bash

# Test parameters
TEST_FILE="/mnt/efs/benchmark.dat"
BLOCK_SIZES="4k 8k 16k 64k 1m"
TEST_SIZE="1G"

echo "Filesystem Benchmark Results"
echo "---------------------------"

for bs in $BLOCK_SIZES; do
    echo -n "Block size $bs write: "
    dd if=/dev/zero of=$TEST_FILE bs=$bs count=$(($TEST_SIZE / $bs)) conv=fdatasync 2>&1 | tail -1
    rm -f $TEST_FILE
    
    echo -n "Block size $bs read: "
    dd if=/dev/zero of=$TEST_FILE bs=$bs count=$(($TEST_SIZE / $bs)) > /dev/null 2>&1
    dd if=$TEST_FILE of=/dev/null bs=$bs 2>&1 | tail -1
    rm -f $TEST_FILE
done

Test crash recovery scenarios:

# Simulate power failure during write
#!/bin/bash

TEST_FILE="/mnt/efs/crash_test.db"
echo "Beginning crash test..."
sqlite3 $TEST_FILE "CREATE TABLE test(id INTEGER PRIMARY KEY, data TEXT);"

# Start infinite insert loop
sqlite3 $TEST_FILE "BEGIN; \
    WITH RECURSIVE cnt(x) AS (VALUES(1) UNION ALL SELECT x+1 FROM cnt WHERE x<100000) \
    INSERT INTO test(data) SELECT randomblob(1000) FROM cnt;" &

# Kill process abruptly after delay
sleep 5
pkill -9 sqlite3

# Verify database integrity
sqlite3 $TEST_FILE "PRAGMA integrity_check;" > integrity.log

Validate permission handling across users:

# Permission test script
#!/bin/bash

TEST_DIR="/mnt/efs/permission_test"
mkdir -p $TEST_DIR

# Test different permission scenarios
for perm in 755 700 644 600; do
    touch "$TEST_DIR/test_$perm"
    chmod $perm "$TEST_DIR/test_$perm"
    
    sudo -u nobody ls -l "$TEST_DIR/test_$perm" >> permission_test.log 2>&1
    sudo -u nobody cat "$TEST_DIR/test_$perm" >> permission_test.log 2>&1
done

When planning a filesystem migration (like ext3 to EFS), comprehensive testing should cover:

• Performance benchmarks (IOPS, throughput, latency)
• Data integrity verification
• Concurrent access patterns
• Failure recovery scenarios
• Permission and ACL handling

For Linux-based systems, these tools provide comprehensive coverage:

# Basic disk benchmarking
sudo hdparm -Tt /dev/sdX

# Filesystem stress testing
sudo apt-get install fio
fio --name=test --ioengine=libaio --rw=randrw --bs=4k --numjobs=16 --size=1G --runtime=300 --group_reporting

When moving from ext3 to EFS (Amazon Elastic File System), consider:

# Mount comparison testing
sudo mount -t ext3 /dev/sdX /mnt/ext3
sudo mount -t nfs4 fs-XXXXXXXX.efs.aws-region.amazonaws.com:/ /mnt/efs

# Permission mapping verification
getfacl /mnt/ext3/testfile > ext3_acl.txt
setfacl --restore=ext3_acl.txt /mnt/efs/testfile

Python script for basic filesystem verification:

import os
import hashlib
import unittest

class FilesystemTest(unittest.TestCase):
    TEST_FILE = "/mnt/test_fs/testfile"
    
    def test_write_read(self):
        test_data = os.urandom(1024)
        with open(self.TEST_FILE, 'wb') as f:
            f.write(test_data)
        
        with open(self.TEST_FILE, 'rb') as f:
            read_data = f.read()
        
        self.assertEqual(
            hashlib.md5(test_data).hexdigest(),
            hashlib.md5(read_data).hexdigest()
        )

if __name__ == '__main__':
    unittest.main()

Key metrics to capture during testing:

# Capture latency metrics using iostat
iostat -xmdz 1

# Network-specific metrics for EFS
sudo apt-get install nfs-common
nfsiostat 1

For enterprise deployments, consider:

• Failover testing with multiple AZs
• Encryption/decryption performance impact
• Mixed workload patterns (small vs large files)
• Long-term stability testing (7+ days)