On Wed, Jul 2, 2008 at 8:30 PM, Marvin Renich <[EMAIL PROTECTED]> wrote: > * Bernd Eckenfels <[EMAIL PROTECTED]> [080701 20:45]: >> In article <[EMAIL PROTECTED]> you wrote: >> >> I mean the pending-write case is the most obvious. But what about resolver >> >> caches, VPNs and the like? >> > >> > What kind of data loss do you expect to arise from shutting down a VPN >> > client without giving it time to save state? >> >> I dont expect any data loss - hopefully protocols are not that >> optimistic/broken. But with unclean shutdown you can affect external parties >> with unexected errors. Like resolver problems, user not found and similiar >> problems. >> > > Either I don't understand the usage scenario you are talking about, or I > misunderstand what is being proposed in this thread, or you > misunderstand what is being proposed in this thread. Here is a more > concrete example of a situation based on what I think is being proposed: > > The Debian maintainer for a specific VPN decides it does not need > special shutdown handling, so he marks it to not require calling > "/etc/init.d/SuperVPN stop" when doing a shutdown or reboot. This is > what I understand this thread is about. This will result in SuperVPN > not being stopped until the final "kill all remaining processes" step of > the halt or reboot (i.e. don't waste time shutting this daemon down > cleanly, let it die abruptly just before halting). > > Now, some other unrelated app, possibly a Debian-provided package and > possibly one installed manually by the sysadmin, uses this VPN and needs > it to be running during the app's normal shutdown (done using the > traditional /etc/init.d/* script) to avoid data loss. The sysadmin or > Debian maintainer will know that a clean shutdown is required, so will > not mark this init script as "skippable" during the normal shutdown > sequence. > > When the system shuts down, since this other app is not explicitly > marked as "safe to kill without init script during system shutdown", its > init script gets called as usual during shutdown. At this point, the > VPN is still up, because the "kill all processes" only happens _after_ > all init scripts have been called for running daemons. > > What is the problem you think might occur with the proposal from this > thread? We can add even more flexibility: You may leave today's scripts as they are, and add "skippable" flag somewhere around LSB headers or /etc/default/<name>. Then if system administrator will have some weired situation where he should like to perform explicit shutdown for particular service - it can just unset "skippable" flag for that service.
This will also ease transition - if some service is not explicitly marked as "skippable", then its not skippable, i.e. you surely do not harm init scripts that are not up to date yet. > > ...Marvin > > > -- > To UNSUBSCRIBE, email to [EMAIL PROTECTED] > with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED] > > -- Zaar -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
