From owner-freebsd-current@FreeBSD.ORG Thu Mar 27 19:22:13 2008 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 939D5106566B for ; Thu, 27 Mar 2008 19:22:13 +0000 (UTC) (envelope-from julian@elischer.org) Received: from outB.internet-mail-service.net (outb.internet-mail-service.net [216.240.47.225]) by mx1.freebsd.org (Postfix) with ESMTP id 8088A8FC23 for ; Thu, 27 Mar 2008 19:22:13 +0000 (UTC) (envelope-from julian@elischer.org) Received: from mx0.idiom.com (HELO idiom.com) (216.240.32.160) by out.internet-mail-service.net (qpsmtpd/0.40) with ESMTP; Thu, 27 Mar 2008 17:44:19 -0700 Received: from julian-mac.elischer.org (localhost [127.0.0.1]) by idiom.com (Postfix) with ESMTP id 4EAA12D6010; Thu, 27 Mar 2008 12:22:12 -0700 (PDT) Message-ID: <47EBF3E4.4000607@elischer.org> Date: Thu, 27 Mar 2008 12:22:12 -0700 From: Julian Elischer User-Agent: Thunderbird 2.0.0.12 (Macintosh/20080213) MIME-Version: 1.0 To: Kurt Jaeger References: <47E9448F.1010304@ipfw.ru> <20080326142115.K34007@fledge.watson.org> <20080327062556.GE3180@home.opsec.eu> In-Reply-To: <20080327062556.GE3180@home.opsec.eu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-fs@freebsd.org, freebsd-current@freebsd.org Subject: Re: unionfs status X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 27 Mar 2008 19:22:13 -0000 Kurt Jaeger wrote: > Vadim Goncharov wrote: >> Robert Watson wrote: > >>> If you're using unionfs >>> to take a template system and "broadcast it" to many jails, you probably don't >>> want all the jails talking to the same syslogd, you want them each talking to >>> their own. When syslogd in a jail finds a disconnected socket, which is >>> effectively what a NULL v_socket pointer means, in /var/run/log, it should be >>> unlinking it and creating a new socket, not reusing the existing file on disk. > >> This code's use in jails is primarily intended for mysql (and the like >> daemons), not syslogd (for which you said it right). Such daemons really >> require broadcasting, yep - so unionfs should support it... > > Thanks for this description. So we basically have two different > uses for UNIX sockets in unionfs with jails ? > > 1) socket in jail to communicate only inside one jail (syslog-case) > 2) socket in jail as a means of IPC between different jails (mysql-case) > > Is 2) really supposed to work like this ? think about it.. the socket is a file interface to a process. if you are reading the same socket, you expect to get the same process. in (1) you put the socket somewhere not shared. in (2) you put the socket somewhere shared. in nullfs you are allowing access to the same vnode via several namespaces positions. A new socket is visible to all jails. In unionfs a new socket would replace the old one and thus be only locally visible (refers to a different vnode to those accessed by the same name in other mounts). >