section 2

“hp extends virtualization to the array”

 

 

—by D.H. Brown Associates, Inc.

reliability characteristics of hp’s

(consisting of all the even-numbered disk slots). Data

va7000 series

movement and failover occur in the same manner

• redundant, hot swappable controllers, fans,

as in the VA7100.

2

The variation in data management at the array level

power supplies, and an internal fibre-channel

hub eliminates planned downtime

provides great flexibility in matching performance

• online firmware and capacity upgrade

to application need. Self-tuning enables immediate

using mixed capacity disk drives

response to data and application variables

• Checksum algorithm used for end-to-end

ensuring more work completed per transaction

data and data-path protection against

and maintaining more consistent service-level

data corruption

performance. RAID 1+0 uses a large number of

• double parity supports recovery from two

disks in a single configuration to deliver strong

simultaneous disk failures (RAID 5DP)

performance to selected LUNs. It does so, however,

• error Correction Code (ECC) protects mirrored

at the expense of additional space for mirroring

cache from corruption before writing to disk

the data. RAID 5DP incurs a performance penalty

• three-day battery backup protects user data

for write operations and can affect system

in cache from power outages and disasters

performance if frequent updates to large volumes

• phone-home capability is provided

of data are required. Its advantage is in the data

redundancy provided and the improved cost

through hp’s Predictive Support programs

and Event Monitoring Services (EMS)

efficiency vs. mirroring. Dual-redundancy groups

 

in the VA7400 enhance the efficiency of data

“Redundancy groups” are physical disks that contain

movement through

the controllers, improving

 

 

 

redundant (copies of) data, defined by the RAID

system performance.

 

type assigned to the data. Each redundancy

 

group is divided into LUNs, addressable by a host.

 

The VA7100 supports only one “redundancy

 

group” with each of the 15 disk drives in the

 

enclosure addressable by both controllers with

 

no physical restrictions. The two fibre-channel

 

loops (one to each controller) include a transmit

 

line and a receive line for the transfer of data to

 

and from the controller. Controller-to-controller

 

communication and loop failover occur via an

 

internal N-way bus.

 

The VA7400 supports two redundancy groups in

 

which one controller manages access to one redundancy

 

group (consisting of all the odd-numbered disk

 

slots) and the other controller to the second group

 

 

 

 

Technology Trends

 

Copyright © 2001 by D.H. Brown Associates, Inc.

 

 

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