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Re: More on vinum woes

From: Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>
Date: Tue, 13 Sep 2005 00:00:35 -0700 (PDT)

:and if I need to provide anything else I can reproduce this panic
:at will. 
:> I far prefer a hardware raid solution (like the 3ware, which we
:> support very well).
:The problem I have with hardware raid solutions is a subset of the
:problem I'm having with operating systems and hardware at the
:moment. Hardware moves too fast, like fast food. 5 years from now when
:my ultra reliable RAID has a card failure, how can I fix it?
:( Obviously, I have to buy three of the hardware RAID cards I use to
:make sure I have two hot spares so I can recover my data should the
:card die. =/ )
:By contrast, software raid lives on, as long as it can read the disks.
:It shouldn't (not sure if it actually does in some cases) matter what
:the controller is. My RAID is not in need of blinding speed, it's just
:for personal and business data for maybe three people. 
:Dave Hayes - Consultant - Altadena CA, USA - dave@xxxxxxxxxxx 
:>>> The opinions expressed above are entirely my own <<<
:Do not look at my outward shape, but take what is in my hand.     
:                                                       -Rumi

    True to a degree, but I think software raid is even worse.  Machines
    evolve, and new ATA chipsets come along which we might not support, 
    or might not support reliably.... just look at all the bug reports 
    FreeBSD gets related to ATA chipsets, and we aren't any better since
    our ATA code is essentially the same.  Nor is linux.  Even windoz
    boxes often have issues requiring BIOS upgrades or driver upgrades.

    DMA issues and actual data corruption can occur quite easily.  The 
    fact that data corruption can occur so easily with these ATA chipsets
    scares me.

    The best hardware raid cards, like the 3ware, have very clear and
    succinct software protocols and run over a hardware bus standard 
    (i.e. the very well understood PCI* bus protocols) that I believe
    results in far better stability in the face of evolving hardware.
    3ware in particular has done a really good job keeping their protocols
    clean across many card models.  You don't even need their software 
    to setup most disks, you just hit ALT-3 while the machine is booting
    and pop into the BIOS.  The cards are fairly cheap considering what they
    do, and you can buy a battery backup daughterboard for any 9000 series
    card (which I may just do). 

    And lets not even talk about the idiotic not-really-hardware-raid
    controllers like (I think) the promise.  That reaches a level of
    craziness that makes me shudder.

    I say let a 3ware card talk to the SATA drives and let us communicate
    with the 3ware card using sane, well understood and well supported
    protocols, rather then us trying to keep up with the billions of
    different ATA chipsets most of which have hardware that is so buggy
    their vendors have to come out with a new chipset rev every few weeks.
    I have to say, the 3ware cards have made a believer out of me.

					Matthew Dillon 

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