rds_piops.py

import getopt
import math
import sys


db_iops_limits = {
    "aurora": {
        "MinimumStorage": 100,
        "MaximumStorage": 6000,
        "TheoreticalMaximumIOPS": 30000
    },
    "mariadb": {
        "MinimumStorage": 100,
        "MaximumStorage": 6000,
        "TheoreticalMaximumIOPS": 30000
    },
    "MySQL": {
        "MinimumStorage": 100,
        "MaximumStorage": 4000,
        "TheoreticalMaximumIOPS": 30000
    },
    "oracle-sel": {
        "MinimumStorage": 100,
        "MaximumStorage": 6000,
        "TheoreticalMaximumIOPS": 25000
    },
    "oracle-se": {
        "MinimumStorage": 100,
        "MaximumStorage": 6000,
        "TheoreticalMaximumIOPS": 25000
    },
    "oracle-ee": {
        "MinimumStorage": 100,
        "MaximumStorage": 6000,
        "TheoreticalMaximumIOPS": 25000
    },
    "postgres": {
        "MinimumStorage": 100,
        "MaximumStorage": 6000,
        "TheoreticalMaximumIOPS": 30000
    },
    "sqlserver-se": {
        "MinimumStorage": 100,
        "MaximumStorage": 6000,
        "TheoreticalMaximumIOPS": 20000
    },
    "sqlserver-ee": {
        "MinimumStorage": 100,
        "MaximumStorage": 6000,
        "TheoreticalMaximumIOPS": 20000
    },
    "sqlserver-ex": {
        "MinimumStorage": 100,
        "MaximumStorage": 6000,
        "TheoreticalMaximumIOPS": 20000
    },
    "sqlserver-web": {
        "MinimumStorage": 100,
        "MaximumStorage": 6000,
        "TheoreticalMaximumIOPS": 20000
    }
}


def get_iops_limits(storage, engine):
    """
    Gets the IOPS limitations for a given RDS database engine.
    Args:
        storage (float): The amount IO1 SSD storage in GB.
    Returns:
        iops_limits A dictionary containing the IOPS limits for
        a given RDS database engine.
    Throws:
        ValueError if the RDS engine is unknown or
            storage is less than the minimum storage or
            greater than the maximum storage.
    """
    iops_limits = db_iops_limits.get(engine)

    if not iops_limits:
        raise ValueError("Unknown RDS engine: %s" % engine)
    elif storage < iops_limits['MinimumStorage'] or \
            storage > iops_limits['MaximumStorage']:
        raise ValueError(
            "Storage (%s) must be between %s and %s" % (
                storage,
                iops_limits['MinimumStorage'],
                iops_limits['MaximumStorage']
            )
        )

    iops_limits['MinimumRatio'] = 3
    iops_limits['MaximumRatio'] = 10
    iops_limits['Incriment'] = 1000

    return iops_limits


def valid_iops(storage, engine):
    """
    AWS RDS Provisioned IOPS calculator.
    IOPS is a measurement of I/O throughput usage. Baseline performance
    scales at a rate of iops:storage in incriments of 1000,
    where one IOPS is equal to up to 16KiB of disk I/O
    and storage equals 1GB ranging from 3:1 to 10:1.
    Args:
        storage (float): The amount IO1 SSD storage in GB.
        engine (string): The RDS database engine, e.g. postgres.
    Returns:
        A list of valid IOPS.
    Throws:
        ValueError if the RDS engine is unknown or
            storage is less than the minimum storage or
            greater than the maximum storage.
    """
    iops_limits = get_iops_limits(storage, engine)
    minimum_iops = int(math.ceil(
        storage * iops_limits['MinimumRatio'] / iops_limits['Incriment']
    )) * iops_limits['Incriment']
    maximum_iops = int(math.floor(
        storage * iops_limits['MaximumRatio'] / iops_limits['Incriment']
    )) * iops_limits['Incriment']

    if maximum_iops > iops_limits['TheoreticalMaximumIOPS']:
        maximum_iops = iops_limits['TheoreticalMaximumIOPS']

    return [
        iops for iops in range(
            minimum_iops,
            maximum_iops + iops_limits['Incriment'],
            iops_limits['Incriment']
        )
    ]


def is_valid_iops(iops, storage, engine):
    """
    Checks if the IOPS value is valid for a given volume.
    Args:
        iops (int): Disk I/O operations per second.
        storage (float): The amount IO1 SSD storage in GB.
        engine (string): The RDS database engine, e.g. postgres.
    Returns:
        True if the IOPS value is valid for a given volume
    Throws:
        ValueError if the RDS engine is unknown or
            storage is less than the minimum storage or
            greater than the maximum storage.
    """
    return iops in get_valid_iops(storage, engine)


def minimum_iops(storage, engine):
    """
    AWS RDS minimum Provisioned IOPS calculator.
    Args:
        storage (float): The amount IO1 SSD storage in GB.
        engine (string): The RDS database engine, e.g. postgres.
    Returns:
        iops The lowest possible IOPS value for a given volume.
    Throws:
        ValueError if the RDS engine is unknown or
            storage is less than the minimum storage or
            greater than the maximum storage.
    """
    return valid_iops(storage, engine)[0]


def maximum_iops(storage, engine):
    """
    AWS RDS maximum Provisioned IOPS calculator.
    Args:
        storage (float): The amount IO1 SSD storage in GB.
        engine (string): The RDS database engine, e.g. postgres.
    Returns:
        iops The highest possible IOPS value for a given volume.
    """
    return valid_iops(storage, engine)[-1]


if __name__ == '__main__':
    engine = 'postgres'
    options, argv = getopt.getopt(sys.argv[1:], 'he:', ['help', 'engine='])

    for option, argument in options:
        if option in ('-h', '--help'):
            print('usage')
            sys.exit(0)
        elif option in ('-e', '--engine'):
            engine = argument

    for arg in argv:
        print("%-6s%s" % (arg + ':', str(valid_iops(float(arg), engine))))