Hot-Plug Hard Disk Drives; Storage Technologies; Hard Drive Technology; Array Controller Technology - Compaq ProLiant 8000 Technology Brief

RAID – Redundant Array of
Independent Disks
TC000603TB
T B
ECHNOLOGY RIEF
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Hot-Plug Hard Disk Drives

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The ProLiant 8000 supports up to three Wide Ultra-3 SCSI internal drive cages. Each ProLiant
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8000 internal drive cage can support a maximum of seven 1-inch hot-plug drives (for a total of 21
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drives with all three drive cages installed). When the server is configured for maximum capacity, it
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can support 382 GB of internal storage. Capacity will increase in the future as new drive
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technologies emerge.
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S T
T O R A G E E C H N O L O G I E S
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As corporations commit more critical information to computers, the requirements for more storage
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capacity and faster data movement are increasing at a startling rate. The Compaq ProLiant 8000
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server includes new storage technologies that help meet these requirements. New hard drive
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technology and a specially designed array controller allow the ProLiant 8000 server to deliver the
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highest levels of internal storage capacity faster and with more reliability.
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Hard Drive Technology

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The Compaq ProLiant 8000 server uses low-voltage differential (LVD) Ultra-3 SCSI hard drives.
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These new one-inch drives allow the ProLiant 8000 server to support 21 total drives—three drive
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cages with seven hard drives each—for a maximum internal storage capacity of 382 GB of data.
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Ultra-3 SCSI hard drives use a 16-bit bus and a double pumped 40-MHz clock rate to achieve
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maximum transfer rates of 160 MB/s. This bus speed provides the performance demanded by
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today's data-intensive applications and prevents system performance from becoming I/O limited as
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drive throughputs increase.
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Although the ProLiant 8000 server supports Wide Ultra-3 SCSI hard drives, the internal drive
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cages and the Wide Ultra-3 SCSI buses will run in Wide Ultra SCSI mode with the Smart Array
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4250ES controller, which is a Wide Ultra SCSI device.
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Array Controller Technology

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The ProLiant 8000 server supports up to two Compaq Smart Array 4250ES controllers—providing
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high-performance and ease-of-use features. The Smart Array 4250ES controller offers three Wide
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Ultra SCSI channels, allowing a single controller to support all three internal hot-plug hard drive
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cages in the new ProLiant 8000 server. Since all three drive cages run off the same RAID engine,
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all 21 internal hot-plug hard drives can be configured as one massive 382-GB array or multiple
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smaller arrays.
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Additionally, the Smart Array 4250ES controller uses a 64-bit PCI Hot Plug extended SCSI
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connector and a cable-less design that is optimized for the ProLiant 8000 server. The extended
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SCSI connector gives customers the flexibility to accommodate both 64-bit and 32-bit technology.
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The cable-less design allows the hard drive cages to be directly connected to the I/O board itself,
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not the array controller. This means much easier PCI Hot Plug usage and the elimination of
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cumbersome loop-back cables.
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The Smart Array 4250ES controller supports RAID levels 0, 0+1, 1, 4, and 5. In addition, the
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controller uses a Compaq developed RAID 5 engine that optimizes RAID 5 performance. The
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controller also supports online spares, which improves overall system fault tolerance by
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automatically replacing a failed drive and quickly restoring the system to full RAID protection.
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The Smart Array 4250ES controller includes a robust 64 MB of battery-backed read/write cache.
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Rechargeable batteries are integrated into the cache, which is actually a removable card installed
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onto the Smart Array 4250ES controller base card. The removable DRAM and batteries keep
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posted-write data secure in the unlikely event that the base controller board should fail. If a system
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