SATA RAID CARD ROUNDUP

AMCC 3ware 9500S-8

The AMCC 3ware 9500S-8 is an 8-port PCI-X RAID controller, which has been quite popular amongst power users and enthusiasts.  It is relatively new to the RAID scene, but has quickly established a name for itself.  Below are images of the card and the contents of its retail packaging:

The 9500S-8 is also known as the "3ware Escalade".  It has an SO-DIMM slot for memory used by the RAID processor as cache, and is populated with a 128MB Centon module.  This board clearly shows each pair of ports adjacent to a Marvell 8818030 PATA-SATA bridge chip, indicating that this design is simply an adaptation of an older PATA RAID card.  Aside from delays and latencies introduced by additional logic in the data path, each pair of SATA ports are actually connected to the same PATA port on the RAID processor just like master and slave drives, possibly reducing performance further.  It uses a 64-bit PCI connector up to 66MHz, and there is no buzzer on board.  Click on the thumbnails below to see details photos of the card itself:

Here are some specs from the AMCC website:

• Optimized hardware XOR RAID 5 engine provides true hardware based RAID and intelligent drive management functions
• Supports RAID levels 0, 1, 10, 5, 50, Single Disk (JBOD)
• Single array capacity scales to over 3 terabytes per controller (64-bit LBA support)
• 128 MB of ECC protected SDRAM, upgradable to 256 MB
• Battery Backup Unit (BBU) ready
• Online Capacity Expansion ready
• StorSwitch point-to-point, non-blocking switched architecture for highest performance
• Bootable array support for greater fault tolerance
• Variable stripe size for performance tuning by application
• Multiple array background initialization for immediate data redundancy
• Host controller and drive command queuing for highest performance
• Multiple card support (up to 4) within a system for large storage requirements
• Multiple logical volumes and RAID levels can exist on one card for maximum configuration flexibility
• Legacy and SATA II out of band (OOB) staggered drive spin-up support
• Hot-swap and hot-spare support for data availability
• Dynamic sector repair for robust data protection
• S.M.A.R.T. disk drive monitoring for reliability
• SMTP support for email/pager notification
• Emergency Flash Recovery protects against power failure during firmware upgrades
• Support for drive activity LED
• Flexible task scheduling for increased useability
• Multi-lane connectors based on the Infiniband SFF-8470 specification
• Complete configuration management suite
• 3ware BIOS Manager (3BM) - BIOS configuration tool
• 3ware Disk Manager 2 (3DM 2) - browser-based management tool
• Command Line Interface (CLI) - scriptable configuration tool

AMCC has software allowing users to configure the controller from a browser, not just at POST:

Here are the results of the tests:

HARDWARE RAID_0

Hardware RAID_0, 8x WD Raptor 740GD, 256k stripe size, Write Cache ON

Hardware RAID_0, 8x WD Raptor 740GD, 64k stripe size, Write Cache ON

Comparing this test to the previous test, we see that a smaller stripe size resulted in better performance. 

This test shows the results of having the write cache OFF.  Again, a slight improvement only. 

Hardware RAID_0, 6x WD Raptor 740GD, 64k stripe size, Write Cache ON

Hardware RAID_0, 4x WD Raptor 740GD, 64k stripe size, Write Cache ON

We seem to attain maximum performance with four drives only.  Perhaps this is due to the 4-port design of the RAID ASIC, being multiplied to eight drives by way of the Marvell converters.

Hardware RAID_0, 2x WD Raptor 740GD, 64k stripe size, Write Cache ON

Overall, write performance was poor in the ATTO tests, but very good in the HD Tach tests. 

HARDWARE RAID_1

Hardware RAID_1, 2x WD Raptor 740GD, Write Cache ON

Again, poor write speeds in the ATTO test, but others were consistent with single-drive numbers.  RAID_1 usually results in better reads, but not always. 

HARDWARE RAID_5

Hardware RAID_5, 8x WD Raptor 740GD, 64k stripe size, Write Cache ON

Hardware RAID_5, 6x WD Raptor 740GD, 64k stripe size, Write Cache ON

Hardware RAID_5, 4x WD Raptor 740GD, 64k stripe size, Write Cache ON

SOFTWARE RAID_0

Software RAID_0, 8x WD Raptor 740GD

Software RAID_0, 6x WD Raptor 740GD

In the software RAID tests, having 6 drives shows slightly better performance over four drives. 

Software RAID_0, 4x WD Raptor 740GD

Software RAID_0, 2x WD Raptor 740GD