Date: Tue, 13 Oct 1998 00:22:12 -0700 From: Don Lewis <Don.Lewis@tsc.tdk.com> To: "Justin T. Gibbs" <gibbs@plutotech.com>, Terry Lambert <tlambert@primenet.com> Cc: Don.Lewis@tsc.tdk.com, julian@whistle.com, freebsd-fs@FreeBSD.ORG, freebsd-scsi@FreeBSD.ORG Subject: Re: filesystem safety and SCSI disk write caching Message-ID: <199810130722.AAA14971@salsa.gv.tsc.tdk.com> In-Reply-To: "Justin T. Gibbs" <gibbs@plutotech.com> "Re: filesystem safety and SCSI disk write caching" (Oct 13, 12:59am)
next in thread | previous in thread | raw e-mail | index | archive | help
On Oct 13, 12:59am, "Justin T. Gibbs" wrote: } Subject: Re: filesystem safety and SCSI disk write caching } I'm still unclear as to whether Don was turning off power or hitting what I } consider the reset button. His comment about UPSes use makes me think he } was testing power outage scenarios. I was hitting the reset button to test the softupdates code because I thought that write caching on the drive was disabled. It wasn't until I got the unexpected filesystem inconsistency that I actually checked the state of the write caching bit. Once I disable write caching, I didn't get any more unexpected inconsistencies, though I didn't repeat this experiment enough to totally convince myself that my results were conclusive. With write caching disabled, I'd expect the same results with either the reset button or the power switch, but I didn't test the latter since it's a lot rougher on the hardware. If the inconsistency was due to a missing softupdates dependency, I'd expect to see more inconsistencies in the many panics I provoked in some other testing I was doing. With the exception of some inconsistencies created by bugs in fsck that corrupted the filesystem while attempting to fix it, I did not see any unexpected inconsistencies caused by these panics. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199810130722.AAA14971>