Messages in this thread | | | Date | Thu, 27 Aug 2009 23:50:56 +0200 | From | Pavel Machek <> | Subject | Re: [patch] document flash/RAID dangers |
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Hi!
> The other thing about this thread is that the only RAID implementation > that is being discussed here is the MD RAID stack. There are a lot of > RAID implementations that have the same issues: > > - motherboard (aka "fake") RAID - In Linux this is typically mapped with > device mapper via dmraid; AFAIK there is not a tool to scrub (or even > monitor the status of and notify on failure) a Linux DM RAID setup. > > - hardware RAID cards without battery backup - these have the exact same > issues because they cannot guarantee all writes complete, nor can they > keep track of incomplete writes across power failures > > - hardware RAID cards _with_ battery backup but that don't periodically > test the battery and have a way to notify you of battery failure while > Linux is running > > The issues being raised here are not specific to extX, MD RAID, or Linux > at all; they are problems with non-"enterprise-class" RAID setups. > There's a reason enterprise-class RAID costs a lot more money than the > card you can pick up at Fry's. > > There's no reason to document the design issues of general RAID > implementations in the Linux kernel.
Even when we carry one of those misdesigned implementations in-tree? (Note that fixed implementations do exist -- AIX? -- just add journal).
'I wont't tell you that this pony bites, because many ponies do bite'?
WTF? I thought we had higher moral standard than this.
Pavel
-- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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