Re: About removable disks, mountroot and sw-raid

From: Doug White (dwhite_at_gumbysoft.com)
Date: 01/14/04

  • Next message: Poul-Henning Kamp: "Re: About removable disks, mountroot and sw-raid" 
    Date: Wed, 14 Jan 2004 11:03:50 -0800 (PST)
To: David Brinegar <david.brinegar@acm.org>

    On Tue, 13 Jan 2004, David Brinegar wrote:

    > Poul-Henning Kamp wrote:
    > > B: Slow boot
    > > Machine boots kernel, disk dribble in at a rate of one
    > > every 20 seconds as the cabinet powers them up.
    >
    > Power dribble reminds me of usb disks that are slow to power up
    > completely. The system detects the disk then outraces it, getting a
    > failed attempt to query device size because the disk needs another
    > second or two to come all the way up. It would be nice to be able
    > to tune the stall in the disk driver before declaring the device not
    > ready.

    Good point about USB. In the SCSI case, every cabinet I've ever seen sets
    the disks to start on START UNIT and the SCSI BIOS will send it and wait
    until all the disks have spun up (or failed to do so). If hardware RAID is
    involved and then this is totally irrelevant.

    It would be nice to make the wait tunable since most conditions won't
    require it and there's no sense in delaying everyone's boot for a few
    bizarre disk setups. 

    -- 
Doug White                    |  FreeBSD: The Power to Serve
dwhite@gumbysoft.com          |  www.FreeBSD.org
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  • Next message: Poul-Henning Kamp: "Re: About removable disks, mountroot and sw-raid"

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