Date: Thu, 05 Jul 2001 11:08:12 -0400 From: Bill Moran <wmoran@iowna.com> To: Dale Hagglund <rdh@best.com> Cc: freebsd-questions@freebsd.org, dnelson@emsphone.com Subject: Re: SCSI bad block remapping Message-ID: <3B4482DC.C3CF1B6C@iowna.com> References: <3B327713.46173EC5@iowna.com> <863d8curun.fsf@ponoka.battleriver.com> <20010704205514.A13653@dan.emsphone.com> <86pubfubp7.fsf@ponoka.battleriver.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Dale Hagglund wrote: > > Dan Nelson <dnelson@emsphone.com> writes: > > > In the last episode (Jul 04), Dale Hagglund said: > > > > (a) the disk might do remapping in fairly large chunks, even > > > up to a track in size, and > > > ... The couple drives I've looked at map single blocks. ... > > > > (b) after remapping, the data in the remapped region is > > > undefined. > > > I am extremely skeptical of this. If the data can be remapped, it > > is remapped correctly (that's what all the ECC stuff is for). If it > > cannot be remapped, an error is returned. > > Since this piqued my interest, I tracked down the horse's mouth. > According to the the SCSI-3 Block Commands specification, when a > REASSIGN BLOCKS command is issued the data contained in blocks being > remapped may be modified. Also, the command can fail because it needs > to remap a larger region than the one specified. However, from the > documentation of AWRE and ARRE, it appears that blocks are reassigned > automatically only if the drive firmware can recover the data. > > It looks like the upshot is that you can, as you suggested, turn on > automatic sector remapping without fear of silent data loss. This is good to know. Thank you for taking the time to look into the specs for us, Dan. Now that I know that it is safe to turn on sector remapping, I still don't know _how_ to do it. I'm also still curious about what's going on with a drive that crashes because of bad sectors one day, and then (once reformatted) runs with no problems for over a week (and still running ...) Thanks so far, Bill To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?3B4482DC.C3CF1B6C>