PCIe+ I/O drawers

PCIe+ I/O Drawers: Expanding Server Capabilities

Introduction

PCIe+ I/O drawers are specialized hardware units designed to enhance the input/output (I/O) capabilities of servers. These drawers provide additional expansion slots, allowing enterprises to connect multiple adapters, storage devices, and networking components. Commonly used in high-performance computing environments, PCIe+ I/O drawers help optimize workload distribution, improve data throughput, and ensure redundancy. This article explores their key features, specifications, connectivity, and benefits.

What Are PCIe+ I/O Drawers?

General Description

PCIe+ I/O drawers serve as expansion units for servers, increasing I/O capacity.
They are typically available in 4U or 8U rack-mountable configurations.
These drawers connect to the central electronics complex (CEC) through high-speed 12X DDR cables.

Purpose and Functionality

Provide additional PCIe slots for expansion cards.
Improve system scalability and flexibility.
Enhance redundancy and reliability in enterprise environments.

Key Features and Specifications

IBM 5802 12X I/O Disk Drawer PCIe

4U, 19-inch rack-mountable design.
Contains 10 PCIe 8x I/O adapter slots.
Features 18 hot-swappable SAS disk bays.
Supports both solid-state drives (SSDs) and hard disk drives (HDDs).
Maximum storage capacity of up to 5.4 TB.
Configurable disk bay groups: single group of 18, two groups of nine, or four groups of four or five.
Requires a minimum of:
- Two 12X DDR cables.
- Two AC power cables.
- Two SPCN cables for redundancy.

IBM 5877 12X I/O Drawer PCIe (No Disk)

4U high I/O drawer without disk storage.
Equipped with 10 PCIe slots.
Connects to CEC using 12X DDR cables.

IBM z16 PCIe+ I/O Drawers

Supports up to 12 PCIe+ I/O drawers in maximum configurations.
Each drawer contains 16 I/O slots divided into two domains.
Used for storage, networking, clustering, and cryptographic processing.

General PCIe+ I/O Drawer

Supports up to 16 adapters, with two ports per adapter.
Comes with two power supply units (PSUs) positioned at the top of the drawer.

Connectivity and Compatibility

Connection to CEC

PCIe+ I/O drawers attach to the host CEC via:
- 12X adapter in a GX slot.
- High-speed 12X DDR cables.
IBM Power7 systems utilize the EJ04 GX++ Dual-port 12X Channel Attach adapter to connect with IBM 5802 I/O drawers.

Compatibility and Restrictions

Mixing IBM 5802, 5796, and 7314-G30 on the same loop is not supported.
Mixing IBM 5802 and 5877 is supported, with a maximum of two drawers per loop.
Only 12X DDR cables are supported; 12X SDR cables are not compatible.

Slot Priority and Optimization

Recommended Slot Filling Order (IBM 5802 & 5877)

P1-C1
P1-C4
P1-C2
P1-C5
P1-C3
P1-C6
P1-C7
P1-C8
P1-C9
P1-C10

Best Practices for Performance

Populate slots P1-C1 to P1-C6 first with high-bandwidth adapters.
Use remaining slots for lower-priority adapters to maintain optimal data throughput.

I/O Domains in IBM z16

Structure of I/O Domains

Each PCIe+ I/O drawer in IBM z16 includes two independent I/O domains.
Each domain supports up to 8 I/O features.

Supported Features

FICON Express32S: High-speed fiber connectivity.
OSA-Express7S 1.2: Advanced network interface.
RoCE Express3: Remote Direct Memory Access (RDMA) over Converged Ethernet.
Coupling Express2 LR: High-performance clustering.
Crypto Express8S: Hardware-based cryptographic security processing.

Redundancy and Reliability Considerations

Power and Cable Redundancy

Minimum configuration requires:
- Two 12X DDR cables.
- Two AC power cables.
- Two SPCN cables.
Ensures continuous operation in case of component failure.

System Configuration Impact

The number of supported PCIe+ I/O drawers depends on:
- Server model and architecture.
- Available power and cooling resources.
- Workload distribution and processing requirements.

Advantages of PCIe+ I/O Drawers

Increased Scalability

Allows businesses to expand their server capabilities without upgrading the entire system.
Supports additional networking, storage, and specialized adapters.

Improved System Performance

Reduces data bottlenecks by offloading I/O processing to dedicated adapters.
Enhances overall server response time and efficiency.

Enhanced Reliability and Redundancy

Multiple power supplies and SPCN cables ensure uninterrupted operation.
Reduces risk of downtime due to component failures.

Cost Efficiency

Extends the lifespan of existing server infrastructure by enabling incremental expansion.
Eliminates the need for frequent system replacements.

Conclusion

PCIe+ I/O drawers are essential for enterprises requiring scalable and high-performance computing solutions. With features such as multiple PCIe slots, storage expansion, and robust redundancy mechanisms, these drawers enhance system capabilities without necessitating a full infrastructure overhaul. Whether used in IBM Power7, IBM z16, or other enterprise environments, PCIe+ I/O drawers play a critical role in modern data center efficiency and reliability.

Here are some FAQs on IBM 5802 and IBM z16 PCIe+ I/O drawers:

FAQs

1. What are the key differences between the IBM 5802 and IBM z16 configurations?

IBM 5802 is a 4U, rack-mountable I/O drawer with 10 PCIe slots and 18 SAS hot-swap disk bays, whereas IBM z16 supports up to 12 PCIe+ I/O drawers, each with 16 I/O slots across two domains.

2. How does the IBM 5802 handle storage capacity compared to other PCIe+ I/O drawers?

IBM 5802 provides up to 5.4 TB of storage through 18 disk bays, supporting SSDs or HDDs, while other PCIe+ I/O drawers like IBM 5877 do not include storage bays.

3. What are the specific requirements for setting up an IBM 5802 I/O drawer?

The IBM 5802 requires at least two 12X DDR cables, two AC power cables, and two SPCN cables for redundancy. It must connect to the host system via a 12X adapter in a GX slot.

4. Can you explain the role of the 12X adapter in the IBM 5802 configuration?

The 12X adapter enables high-speed connectivity between the IBM 5802 I/O drawer and the central electronics complex (CEC), ensuring efficient data transfer and system integration.

5. How does the IBM z16 support up to 12 PCIe+ I/O drawers?

IBM z16’s architecture allows up to 12 PCIe+ I/O drawers, each featuring two I/O domains with 16 slots for network, storage, clustering, and cryptography adapters.