Editing RAID (section)

=== <span class="anchor" id="FAKE"></span>Firmware- and driver-based ===
{{See also|MD RAID external metadata}}
[[File:SATA 6 Gbit-s controller, in form of a PCI Express card.jpg|thumb|A [[SATA&nbsp;3.0]] controller that provides RAID functionality through proprietary firmware and drivers]]

Software-implemented RAID is not always compatible with the system's boot process, and it is generally impractical for desktop versions of Windows. However, hardware RAID controllers are expensive and proprietary. To fill this gap, inexpensive "RAID controllers" were introduced that do not contain a dedicated RAID controller chip, but simply a standard drive controller chip, or the chipset built-in RAID function, with proprietary firmware and drivers. During early bootup, the RAID is implemented by the firmware and, once the operating system has been more completely loaded, the drivers take over control. Consequently, such controllers may not work when driver support is not available for the host operating system.<ref>{{cite web |title=SATA RAID FAQ |url=https://ata.wiki.kernel.org/index.php/SATA_RAID_FAQ |publisher=Ata.wiki.kernel.org |date=2011-04-08 |access-date=2012-08-26}}</ref> An example is [[Intel Rapid Storage Technology]], implemented on many consumer-level motherboards.<ref>{{cite web |url=https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Storage_Administration_Guide/s1-raid-approaches.html |title=Red Hat Enterprise Linux – Storage Administrator Guide – RAID Types |website=redhat.com}}</ref><ref name="RusselCrawford2011">{{cite book |first1=Charlie |last1=Russel |first2=Sharon |last2=Crawford |first3=Andrew |last3=Edney |title=Working with Windows Small Business Server 2011 Essentials |url=https://books.google.com/books?id=R2gJ9kcX2ywC&pg=PA90 |year=2011 |publisher=O'Reilly Media, Inc. |isbn=978-0-7356-5670-3 |page=90 |via=[[Google Books]]}}</ref>

Because some minimal hardware support is involved, this implementation is also called "hardware-assisted software RAID",<ref>{{cite web |first=Warren |last=Block |url=http://www.freebsd.org/doc/handbook/geom-graid.html |title=19.5. Software RAID Devices |website=freebsd.org |access-date=2014-07-27}}</ref><ref name="KrutzConley2007">{{cite book |first1=Ronald L. |last1=Krutz |first2=James |last2=Conley |title=Wiley Pathways Network Security Fundamentals |url=https://books.google.com/books?id=Gdux_6ckDYwC&pg=PA422 |year=2007 |publisher=[[John Wiley & Sons]] |isbn=978-0-470-10192-6 |page=422 |via=[[Google Books]]}}</ref><ref name="AdaptecWP" /> "hybrid model" RAID,<ref name="AdaptecWP" /> or even "fake RAID".<ref name="Smith2010">{{cite book |first=Gregory |last=Smith |title=PostgreSQL 9.0: High Performance |url=https://books.google.com/books?id=OWOAu0GcsqoC&pg=PT72 |year=2010 |publisher=[[Packt Publishing]] Ltd |isbn=978-1-84951-031-8 |page=31 |via=[[Google Books]]}}</ref> If RAID&nbsp;5 is supported, the hardware may provide a hardware XOR accelerator. An advantage of this model over the pure software RAID is that—if using a redundancy mode—the boot drive is protected from failure (due to the firmware) during the boot process even before the operating system's drivers take over.<ref name="AdaptecWP">{{cite web |url=http://www.adaptec.com/nr/rdonlyres/14b2fd84-f7a0-4ac5-a07a-214123ea3dd6/0/4423_sw_hwraid_10.pdf |title=Hardware RAID vs. Software RAID: Which Implementation is Best for my Application? Adaptec Whitepaper |website=adaptec.com}}</ref>