From mboxrd@z Thu Jan 1 00:00:00 1970 To: 9fans@9fans.net Date: Fri, 9 Jan 2009 10:44:43 +0100 From: Sape Mullender Message-ID: <10bfefea89ce073c1640dd187f77ec79@plan9.cs.bell-labs.com> In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Subject: Re: [9fans] venti Topicbox-Message-UUID: 7dd6ea34-ead4-11e9-9d60-3106f5b1d025 > i noticed something odd with venti and i am just trying to see if this > is an issue and if this needs to be addressed. > > i think, by default, plan9 installation sets localhost as the address > for venti in plan9.ini. but at some point i wanted venti to announce > any (*) address. for some reason, i simply started venti/venti -a > 'tcp!*!17034' to make it so. after this, i did vac from another > machine and it archived data. after sometime, i realized i may be > running venti on the same venti data area twice. when i did 'ps', it > looked like that. then i rebooted the machine and then tried > 'dumpvacroots.new' command (from contrib). i noticed that venti arena > was corrupted. this is what i remember and if required i can try to > reproduce the issue. > > the question i have is, is there any protection that prevents someone > from doing this accidentally? something like the last active venti > arena is marked 'IN_USE' so that if another instance of venti is > started (with read-write access), it can check for this? i agree user > has to be careful but given that venti archive is so critical, we > should avoid any accidental damage. Hmm. Running two ventis on the same data is, of course, bad. It's also something I haven't seen happen before. A check could be put in by having venti put some sort of lock somewhere on the disk. But that would lead to problems if venti doesn't shut down properly: venti would be gone but the lock would still be there. You run the risk of not being able to boot your machine. I think you should just learn to be careful. Sape