Date: Wed, 1 Oct 2008 02:04:14 -0700 From: Jeremy Chadwick <koitsu@FreeBSD.org> To: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl> Cc: "freebsd-questions@freebsd.org" <freebsd-questions@freebsd.org>, Andrew Falanga <af300wsm@gmail.com> Subject: Re: Setting up gmirror Message-ID: <20081001090414.GA15939@icarus.home.lan> In-Reply-To: <20081001092139.D7677@wojtek.tensor.gdynia.pl> References: <340a29540809302134p2414e3cfw6a0694026e57d879@mail.gmail.com> <20081001071150.GA13554@icarus.home.lan> <20081001092139.D7677@wojtek.tensor.gdynia.pl>
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On Wed, Oct 01, 2008 at 09:22:20AM +0200, Wojciech Puchar wrote: >> with regards to Intel MatrixRAID, here you go: >> >> http://wiki.freebsd.org/JeremyChadwick/ATA_issues_and_troubleshooting >> >> And yes, these are FreeBSD problems, but the severity is so high that >> there is a very good chance you will lose your data in the case of a >> failure. Simply put, don't risk it. > > BIOS RAIDs are software RAIDs. FreeBSD "driver" for this is software RAID > too, just like gmirror but worse and less portable. > > simply doesn't make sense. And what exactly do you classify controllers such as the Promise TX4310 and the Promise S150 SX4 as? The TX4310 could be classified as "software RAID", but a few of the features are offloaded onto the controller. The SX4 is the same way, but has actual on-board cache. You like to declare everything as "software RAIDs", while I like to discern the difference between them using (what I believe to be) more accurate terminology: BIOS-level RAID (Adaptec HostRAID, Intel MatrixRAID; "chipset" RAID) OS-based RAID (gvinum, ccd, etc.) Hardware RAID (LSI Logic, 3Ware, Areca controllers) There is always a certain degree of "software" (specifically, processing/work done on the main system's CPU) in all of those, since there is always a driver involved for interfacing with the cards -- even ones with dedicated CPUs like the Intel IOP/XScale. -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
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