From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: From: jmk@plan9.bell-labs.com To: 9fans@cse.psu.edu Subject: Re: [9fans] venti ports and productization In-Reply-To: <11aaa855361fd5ac7e637be3d37d3116@hamnavoe.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Wed, 22 Oct 2003 12:54:36 -0400 Topicbox-Message-UUID: 77bfd65e-eacc-11e9-9e20-41e7f4b1d025 On Wed Oct 22 10:58:46 EDT 2003, miller@hamnavoe.demon.co.uk wrote: > > We have had some problems > > with the big Venti server, but my understanding is that > > all of the problems appeared to be disk corruption rather > > than software error. > > The software could do a bit better in recovering from hardware errors. > If a bad sector makes a venti block unreadable, rdarena and wrarena > could use the redundant information in the arena trailer to skip the > bad block and continue, but they just give up. Worse, if checkarenas > (with -f) fails to read a block, instead of using the trailer information > to skip the block, it tries to correct the mismatch between block label > and trailer by copying garbage into the trailer entry from the buffer > it just failed to read into. Oops. > > -- Richard That's pretty much right, in my limited experience. When I started looking at the errors we have I hacked up the arena read programme I have to do some resynchronisation, it needs more work, though. Looking at the errors we have, I don't think I'd ever want to write back into the arena to try to fix it, that stuff with VtTypeCorrupt just seems wrong (as does the definition of VtTypeCorrupt as VtMaxType).