Skip site navigation (1)Skip section navigation (2)
Date:      Tue, 13 Oct 1998 22:59:24 -0700
From:      Don Lewis <Don.Lewis@tsc.tdk.com>
To:        "Justin T. Gibbs" <gibbs@plutotech.com>, Don Lewis <Don.Lewis@tsc.tdk.com>
Cc:        Terry Lambert <tlambert@primenet.com>, freebsd-fs@FreeBSD.ORG, freebsd-scsi@FreeBSD.ORG
Subject:   Re: filesystem safety and SCSI disk write caching
Message-ID:  <199810140559.WAA17612@salsa.gv.tsc.tdk.com>
In-Reply-To: "Justin T. Gibbs" <gibbs@plutotech.com> "Re: filesystem safety and SCSI disk write caching" (Oct 13, 11:16pm)

next in thread | previous in thread | raw e-mail | index | archive | help
On Oct 13, 11:16pm, "Justin T. Gibbs" wrote:
} Subject: Re: filesystem safety and SCSI disk write caching
} >} This doesn't follow.  If the cache is disabled, it doesn't matter if
} >} the drive loses power due to hitting the reset button.  We already 
} >} know that losing power on a drive that cached data will not work.
} >
} >I didn't hear the sound of any mechanical things spinning down.  The
} >machine just started going through its boot sequence.
} 
} The drive will reinitialize to the 'power on state' if the power fluctuates
} into a zone that might invalidate it's run-time state.  It doesn't take a
} very long spike for the drive's power-glitch sensor to go off.  In this
} case, dropping cached contents on the floor is much safer than attempting
} to continue from an unknown state.

If that's the reason for the problem that I saw, then the UPS the
system was plugged into wasn't sufficient to prevent the problem.

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-fs" in the body of the message



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199810140559.WAA17612>