On Tue, Aug 16, 2016 at 5:57 AM, Zdenek Kabelac <zkabelac@xxxxxxxxxx> wrote: > Dne 6.8.2016 v 04:08 james harvey napsal(a): >> >> Same problem and question about if an immediate SIGKILL is OK for >> dmeventd. >> >> On Thu, Aug 4, 2016 at 11:20 PM, james harvey <jamespharvey20@xxxxxxxxx> >> wrote: >>> >>> Does it matter at all if lvmetad shuts down gracefully? >>> >>> Can I safely just have systemd right off the bat send a SIGKILL? >>> >>> Most things I wouldn't ask about, but I'm wondering if this is PURELY >>> a caching daemon where gracefully shutting down doesn't really do >>> anything. >>> > > > Sigterm/sigint is ignored by dmeventd when device is monitored. > > Before stopping dmevend - devices shall be unmonitored. > (vg/lvchange) > > Killing 'dmeventd' in the middle of i.e. recovery operation might leave your > system in dizzy state (suspended devices) essentially useless. > > > Somewhat similar ATM does apply to lvmetad - where lvm2 command will not > like death of lvmetad in the middle of operation and this may result in > operation failure (thought here the situation might get somewhat improved > over the time...) - but ATM don't kill - just stop services. > > Fedora should be doing it properly on reboot - switching to ramdisk and > continuing with shutdown sequence from there. Unsure how other OS-es solves > this. > > Using 'kill -9' (SIGKILL) is in general unsupported and any reported > problems caused by this usage are ignored... > > Regards > > Zdenek > Got it. Fedora defaults to having lvm2-monitor.service enabled, Arch doesn't. (I've asked for that to be fixed.) Arch also uses a shutdown ramdisk. A few follow-ups, then: 1) Should the lvm2-lvmetad, dm-event, and lvm2-monitor unit files be modified so they are never given a SIGKILL? Even with lvm2-monitor.service enabled, even on Fedora, if systemd sees they don't SIGTERM/SIGINT within 90 seconds (systemd v231 is 90 seconds, was 10 second before), it's sending them a SIGKILL. I think adding "SendSIGKILL=no" to the Service and Socket sections will do this, if I understand it correctly. 2) Should lvm2-lvmetad and dm-event systemd unit files want lvm2-monitor.service? 3) Could all LVM programs be changed so if they receive a SIGTERM/SIGINT and choose to ignore it, they give a warn/info/debug message? Not doing so invites thinking a SIGKILL is the proper thing to do. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
