ISS Technology Update, Volume 9, Number 3

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HP ISS Technology Update

Volume 9, Number 3

Keeping you informed of the latest ISS technology

Enabling physical drive write cache on HP Smart Array controllers ............................................................ 2

Does HP Enclosure Dynamic Power Capping affect individual server blade performance? ............................ 3

Meet the Expert—Chad Mar ................................................................................................................. 5

Contact us .......................................................................................................................................... 6

Recently published Industry-Standard Server technology papers

Title

URL

HP ProLiant AMD-based 100-series G7 servers

http://h20000.www2.hp.com/bc/docs/support/SupportMa

nual/c02157764/c02157764.pdf

HP ProLiant AMD-based 300-series G7 servers

http://h20000.www2.hp.com/bc/docs/support/SupportMa

nual/c02160131/c02160131.pdf

HP ProLiant Intel-based 300-series G6 and G7

servers

http://h20000.www2.hp.com/bc/docs/support/SupportMa

nual/c00502616/c00502616.pdf

The AMD processor roadmap for industry-

standard servers, 7th edition

http://h20000.www2.hp.com/bc/docs/support/SupportMa

nual/c00428708/c00428708.pdf

DDR3 memory technology

http://h20000.www2.hp.com/bc/docs/support/SupportMa

nual/c02126499/c02126499.pdf

ProLiant 100-series Intel-based G6 servers, 4th

edition

http://h20000.www2.hp.com/bc/docs/support/SupportMa

nual/c01751718/c01751718.pdf

HP Industry Standard Server technical papers can be found at www.hp.com/servers/technology

Summary of content (6 pages)

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2 HP ISS Technology Update Volume 9, Number 3 Keeping you informed of the latest ISS technology Enabling physical drive write cache on HP Smart Array controllers ............................................................ 2 Does HP Enclosure Dynamic Power Capping affect individual server blade performance? ............................ 3 Meet the Expert—Chad Mar ................................................................................................................. 5 Contact us ..................
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Enabling physical drive write cache on HP Smart Array controllers HP Smart Array RAID controllers use controller-level write cache to improve the local storage subsystem write performance of ProLiant servers. Controller write cache acts as an output buffer, allowing server applications to post write commands to the controller without having to wait for the write operation to complete to disk. The Smart Array controller then executes the lowlevel write operations.
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Risks of enabling physical drive write cache Unlike controller-level cache, individual drive write caches are not protected. If the server loses power or if a hot plug drive is physically removed from the array during operations, unwritten data in the physical drives’ write caches will be lost. Although this window of vulnerability is fairly small, it still exists. Therefore, HP drives have drive write cache disabled by default.
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power caps of busier server blades and decrease the caps of less busy server blades. This power reallocation process is repeated every 20 seconds. Normally, the OA software can quickly raise a low power cap for an idle server blade when it receives new work with little overall impact on enclosure performance. And if the power demand of all the server blades exceeds the available energy, the OA will share the available power among all busy server blades.
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Meet the Expert—Chad Mar With more than 23 years of experience at HP/Compaq, Chad Mar has displayed a rare combination of knowledge, intellect, and leadership that exemplifies HP leadership in server technology. Currently, Chad is a Project Manager for ISS Shared Engineering Services with responsibilities that include the next generation iLO technology, systems troubleshooting, and technology investigations.
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Contact us Send comments about the ISS Technology Update to TechCom@HP.com. To subscribe to the ISS Technology Update, click mailto:techcom@hp.com?subject=TechUpdate_subscription Past articles can be found at http://h18004.www1.hp.com/products/servers/technology/whitepapers/general.html#archive. Follow us on Twitter: http://twitter.com/ISSGeekAtHP Legal Notices © Copyright 2010 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.