AIX > Storage > Flash

Introducing IBM Flash Adapter 90


Flash-based data storage is next wave of computing technology. Flash provides significant improvements in IOPS and reduced latency when compared to traditional disk-based systems. Flash-based technology is currently available in SSD, PCIe card and SAN-based form factors. This article provides an overview of a PCIe-based offering, the IBM Flash Adapter 90. Announced in October 2013, this adapter provides a high performance, low-cost entry into flash-based storage.

Technical Overview

The IBM Flash Adapter 90 is a PCIe Gen2 flash-based adapter that provides up to 325,000 read IOPS and less than 100 microsecond latency. A total of 900 GB useable, RAID protected storage is provided per adapter card. The RAID implementation is based on the same technology used in the IBM FlashSystem external disk drawer. This includes the patented Variable Stripe RAID (VSR). VSR significantly reduces the amount of storage that’s taken offline in the presence of defective data blocks. Most flash-based systems have fixed stripe sizes and are forced to take a greater amount of storage offline when blocks are marked defective. The IBM Flash Adapter 90 has four integrated controllers, each managing 10 eMLC flash chips. The integrated controllers reduce host system overhead and provide better performance than other solutions, which require host-based RAID management. Note the use of eMLC flash chips, which have a significantly better write cycle life as compared to MLC flash chips. The lower quality MLC flash chips are often used other vendor’s implementations. The IBM Flash Adapter 90 is configured with a total of 1,370 GB of raw storage. This provides approximately 315 GB of on-board, spare capacity. The spare capacity provides automatic substitution for flash chips that may be marked unusable during the useful life of the adapter. Additional reliability features include ECC protection and power outage protection. If your server has an abrupt power-off situation, capacitors integrated on the IBM Flash Adapter 90 provide up to 5 seconds of on-board power to finish any outstanding write operations.

Working With the IBM Flash Adapter 90

The primary objective for the deployment of flash-based storage is to improve application performance. The most common uses for flash storage include full database file sets, database index files, metadata and other highly active file systems. The IBM Flash Adapter 90 shows up to the AIX operating system as a single 900 GB disk drive (hdisk). From an operating system perspective, you assign and use it like any other disk drive. You don’t need to manage the RAID protection on the adapter. The controllers integrated on the adapter handle this. While the adapter provides RAID protection for the flash chips on the adapter, the adapter itself can be considered a single point of failure. You may want to consider installing two adapters and use AIX LVM mirroring for protection against an adapter failure. You can use the IBM Flash Adapter 90 in a variety of ways but here are three common use cases:

  1. High-speed temporary workspace – Operating in this mode, the adapter is use for temporary files that don’t require higher levels of protection offered by RAID between multiple devices or a SAN-based disk subsystem.
  2. Fast read for SAN-based file systems – In this configuration, the adapter is used to supplement an existing, SAN-based disk configuration. Using AIX LVM mirroring, you can establish a local AIX mirror for highly active SAN-based disk LUNs. Setting the flash adapter hdisk to preferred read will dramatically speed up file system reads, providing significantly more IOPS and reduced latency. In the unlikely event of an adapter failure, your data is still protected and available from the SAN.
  3. Full file system on flash – For file systems that will entirely fit onto the flash adapter, the file systems can be mirrored between two flash adapters, which provides protection against an adapter failure.

Since the adapter is internal to the server, it’s not well suited for use in PowerHA clusters unless you have a mechanism in place to replicate the data from the IBM Flash Adapter 90 to the PowerHA cluster partner.

Installation Requirements

The IBM Flash Adapter 90 is currently available for use with IBM Power Systems 720, 730 and 740 servers. IBM has issued a statement of direction to provide future support for additional Power Systems server models. The adapter requires a full-height, half-length PCIe slot. It’s a PCIe Gen2 adapter, so maximum performance will be obtained by placing the adapter into a PCIe Gen2 slot within the server chassis. It can also be installed in a lower bandwidth 5802/5877 IO drawer PCIe Gen1 slot. Up to four adapters can be installed in each server chassis. An additional four adapters can be installed in each attached IO drawer. The IBM Flash Adapter 90 is supported with the following operating system versions:

  • AIX V7.1 with the 7100-03 Technology Level
  • AIX V6.1 with the 6100-09 Technology Level
  • Red Hat Linux Version 6.5 

For AIX implementations, you’ll need to download the IBM Flash Adapter 90 device driver from IBM Fix Central. The device driver package also includes a command line utility called rs_info. This tool can be used to communicate with the adapter and check adapter card details (part number, serial number, firmware, etc.), the status of the card, flash module health state and other data. Note that this adapter cannot be used for AIX boot or with VIO servers.

Consider the Benefits

Flash-based storage is appearing in many form factors in a wide variety of price and performance points. The IBM Flash Adapter 90 adapter provides a relatively low-cost entry into a high performance, high-reliability flash storage solution. You might want to consider implementing this adapter to see how your applications would benefit from a very large increase in IOPS and significantly reduced access latency.

Charlie Cler supports customers in a solutions-architect role at Forsythe Technology Inc. He can be reached at ccler@forsythe.com.


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