Date: Fri, 26 Jan 2007 13:14:14 -0600 From: "Rick C. Petty" <rick-freebsd@kiwi-computer.com> To: "R. B. Riddick" <arne_woerner@yahoo.com> Cc: freebsd-geom@FreeBSD.ORG Subject: Re: clear metadata using dd? Message-ID: <20070126191413.GA70473@keira.kiwi-computer.com> In-Reply-To: <915325.15953.qm@web30303.mail.mud.yahoo.com> References: <20070126055929.GA56183@keira.kiwi-computer.com> <915325.15953.qm@web30303.mail.mud.yahoo.com>
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On Fri, Jan 26, 2007 at 05:57:23AM -0800, R. B. Riddick wrote: > --- "Rick C. Petty" <rick-freebsd@kiwi-computer.com> wrote: > > > Obviously u never had a disk go bad, when put under gmirror. I tried that again Actually I have, and it behaved somewhat well. I was pleasantly surprised. > today. At least with `atacontrol detach/attach` (plus write access with dd to > the raw gmirror device; and I waited between attach and detach until the mirror detach/attach isn't quite the same. > was sync'ed again) I can still produce funny situations in R6.2: The device > ad3s1b was still there and ad3 was not... That doesn't surprise me. There were quite a number of bugs in 6.1 & even still in 6.2. Unfortunately they are difficult to reproduce. > > Does anyone here have SATA disks? I have heard it is easy to pull their plug > and plug it back in... Any real test results here? Yes they sure are. I've had a number of "failures" due to disks dropping off just because their cables came out. In fact on one system, I had the case open and I hit the cable with my foot, the drive dropped, and not realizing this I continued using the system for a few weeks until I noticed that something was missing in systat. Gmirror held up pretty nicely. However, I'm not a big fan of the priority placed on the I/O to sync the disks. Pretty much during a resync, the box is unusable for file/disk I/O for a number of hours. Apps using GNOME/GTK are almost non-responsive, and forget about even using java/eclipse. I haven't found a good way to tune gmirror's sync. I also wish you could pause the sync, restart, and unpause it where it left off. All the GEOM tools are feature lacking, and there's not enough manpower. -- Rick C. Petty
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