Date: Thu, 24 Oct 1996 17:34:33 -0400 From: Bakul Shah <bakul@plexuscom.com> To: dg@Root.COM, dwhite@resnet.uoregon.edu, fenner@parc.xerox.com Cc: questions@freebsd.org Subject: Re: Is my disk going bad? Message-ID: <199610242134.RAA13123@chai.plexuscom.com> In-Reply-To: Your message of "Thu, 24 Oct 1996 13:41:39 PDT." <199610242041.NAA06512@root.com>
next in thread | previous in thread | raw e-mail | index | archive | help
> >> I just noticed that I've been getting these for a while: > >> > >> sd1(ncr0:1:0): MEDIUM ERROR info:119a05 csi:6,a8,3,41 asc:11,43 field replaceable unit: 15 sks:80,40 > >> > >> sd1 is a Quantum 1080S. I don't have the probe messages since the > >> medium error messages have scrolled them away. > >> > >> I just yesterday turned on remapping: > >> > >> % scsi -f /dev/rsd1 -m 1 > >> AWRE (Auto Write Reallocation Enbld): 1 > >> ARRE (Auto Read Reallocation Enbld): 1 > >> > >> but it's not remapping, it's still returning errors. > >> > >> Is this the disk going so bad that it can't reallocate to good blocks? > > > >How full is it? Once you've filled the disk then it can't reallocate > >those bad sectors anywhere else. > Uhh, gurp. Drives reserve spare tracks and blocks for use in reallocation. > The space does not come from the filesystem free block pool. If the MEDIUM ERROR was a `hard read error', one that can not be corrected by the block's ECC, the disk is doing the *right thing* by not automatically remapping it. If a block with a hard read error was automatically remapped, the _next_ time this block is read, you *won't* get a read error but any data in this new block is garbage -- so now you have _silent_ data corruption. Automatic remapping only makes sense on a write to a known bad block or on a *soft read error* -- in the latter case the original data _was_ recovered thanks to the ECC and on the chance this block is going bad, the original data is moved to a good block (and the old block number is mapped to the new block). Another (remote) possibility is that the disk has run out of spares.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199610242134.RAA13123>