Re: [gentoo-user] ntp-client slows down the boot process
On Friday, 26 July 2019 16:49:25 BST Rich Freeman wrote: > On Fri, Jul 26, 2019 at 11:32 AM YUE Daian wrote: > > I switched to a faster NTP server. It still takes some seconds but > > better than before. > > > > Maybe you are right. Having correct system time is more important than > > several seconds... > > You're never going to make NTP fast unless you're using a VERY > low-latency server - like something on your own LAN. That is just the > nature of the protocol - it has to do a round trip, and of course to > do anything it needs the interface up, DNS, and so on, and all of > these will be starting from cold caches. If you have non-local DNS > and non-local NTP then that is multiple round-trips to the internet. > > > By the way does "rc_parallel" really makes a difference? > > I tried it once before but did not really see much difference. > > I haven't used OpenRC in ages, but I'm guessing that NTP is set as a > dependency somewhere in the chain. It does make sense - lots of > services do not like abrupt time changes so generic dependencies will > probably assume that you want to set your clocks before starting > anything. > > I'm not sure how ntpdate implements time changes. I know that ntpd > will slew the clock gradually for small corrections, but it is a > daemon so it can easily implement something like that. A one-shot > correction will probably be instant, and thus will be more of an > impact on other services. > > You can probably adjust the dependencies to suit your tastes, but of > course you'll have to keep in mind that time changes for running > services might or might not be a problem. If you're fairly confident > in your hardware clock accuracy (assuming you even have one) that > isn't a big deal. If you're talking about some system that doesn't > keep time when powered off/etc then you probably don't want your > database server to spin up thinking it is 1980 or whatever its epoch > is. > > I did a quick check of what is being done with systemd and ntpdate is > needed before the time-sync target, and that is needed before starting > cron or any timer units (obvious requirement), and it is also required > before spinning up libvirt guests, which also makes sense so that > those initialize with a clean clock, though if they update themselves > maybe that isn't a hard requirement. Just a thought - is the hwclock service in the boot run level and running? I think it will restore the time stored on the hwclock to the system and then gradually update it as the ntp-client starts communicating with various time servers. At least this is how chrony does it. -- Regards, Mick signature.asc Description: This is a digitally signed message part.
Re: [gentoo-user] ntp-client slows down the boot process
On Fri, Jul 26, 2019 at 11:32 AM YUE Daian wrote: > > I switched to a faster NTP server. It still takes some seconds but > better than before. > > Maybe you are right. Having correct system time is more important than > several seconds... You're never going to make NTP fast unless you're using a VERY low-latency server - like something on your own LAN. That is just the nature of the protocol - it has to do a round trip, and of course to do anything it needs the interface up, DNS, and so on, and all of these will be starting from cold caches. If you have non-local DNS and non-local NTP then that is multiple round-trips to the internet. > > By the way does "rc_parallel" really makes a difference? > I tried it once before but did not really see much difference. I haven't used OpenRC in ages, but I'm guessing that NTP is set as a dependency somewhere in the chain. It does make sense - lots of services do not like abrupt time changes so generic dependencies will probably assume that you want to set your clocks before starting anything. I'm not sure how ntpdate implements time changes. I know that ntpd will slew the clock gradually for small corrections, but it is a daemon so it can easily implement something like that. A one-shot correction will probably be instant, and thus will be more of an impact on other services. You can probably adjust the dependencies to suit your tastes, but of course you'll have to keep in mind that time changes for running services might or might not be a problem. If you're fairly confident in your hardware clock accuracy (assuming you even have one) that isn't a big deal. If you're talking about some system that doesn't keep time when powered off/etc then you probably don't want your database server to spin up thinking it is 1980 or whatever its epoch is. I did a quick check of what is being done with systemd and ntpdate is needed before the time-sync target, and that is needed before starting cron or any timer units (obvious requirement), and it is also required before spinning up libvirt guests, which also makes sense so that those initialize with a clean clock, though if they update themselves maybe that isn't a hard requirement. -- Rich
Re: [gentoo-user] ntp-client slows down the boot process
On 2019-07-26 17:15, Ralph Seichter wrote: > * YUE Daian: > >> I added [ntp-client] to the default boot level (OpenRC), however it >> seriously slows down the boot process (around 10 seconds or so). > > Launching 'clamd' can hold up a reboot for a minute or longer, so ten > seconds do not seem that bad to me. > >> Is there any way to make it faster? > > Personally, I gladly wait for a couple of seconds and know that the > clock is correct, but if it bothers you too much, you can try setting > rc_parallel="YES" in /etc/rc.conf . > > -Ralph I switched to a faster NTP server. It still takes some seconds but better than before. Maybe you are right. Having correct system time is more important than several seconds... By the way does "rc_parallel" really makes a difference? I tried it once before but did not really see much difference. Thanks!
Re: [gentoo-user] ntp-client slows down the boot process
On 2019-07-26 15:55, Mick wrote: > On Friday, 26 July 2019 15:23:11 BST YUE Daian wrote: >> On 2019-07-26 09:30, Peter Humphrey wrote: >> > On Friday, 26 July 2019 05:36:29 BST YUE Daian wrote: >> >> Hi folks, >> >> >> >> I use ntp-client to synchronize the date/time of my Gentoo system. >> >> >> >> I added it to the default boot level (OpenRC), however it seriously >> >> slows down the boot process (around 10 seconds or so). >> >> >> >> Is there any way to make it faster? Or am I using the wrong service? >> > >> > It may be taking time to gather entropy. In that case you could install >> > sys- apps/haveged and add it to your boot run-level. >> >> Well, I presume the problem is related to ntpdate itself. >> >> It is working in a blocking way that the remaining boot processes have >> to wait until the time got synchronized. > > Or, until the network is up and a time server can be contacted? > > >> Is there any way to make it update the time in an asynchronize way? >> Or should I use ntpd instead? >> >> Thanks. >> >> Danny > > I don't run ntp-client here, but have a look at its startup script and any > dependencies defined therein, then perhaps tweak /etc/rc.conf. Does setting > rc_depend_strict="NO" makes a difference? > > -- > Regards, > > Mick In fact since my PC is using a wire connection, the network starting process takes very short time. It is the problem of slow NTP itself. I tried "rc_depend_strict" but no luck...
Re: [gentoo-user] ntp-client slows down the boot process
* YUE Daian: > I added [ntp-client] to the default boot level (OpenRC), however it > seriously slows down the boot process (around 10 seconds or so). Launching 'clamd' can hold up a reboot for a minute or longer, so ten seconds do not seem that bad to me. > Is there any way to make it faster? Personally, I gladly wait for a couple of seconds and know that the clock is correct, but if it bothers you too much, you can try setting rc_parallel="YES" in /etc/rc.conf . -Ralph
Re: [gentoo-user] ntp-client slows down the boot process
On Friday, 26 July 2019 15:23:11 BST YUE Daian wrote: > On 2019-07-26 09:30, Peter Humphrey wrote: > > On Friday, 26 July 2019 05:36:29 BST YUE Daian wrote: > >> Hi folks, > >> > >> I use ntp-client to synchronize the date/time of my Gentoo system. > >> > >> I added it to the default boot level (OpenRC), however it seriously > >> slows down the boot process (around 10 seconds or so). > >> > >> Is there any way to make it faster? Or am I using the wrong service? > > > > It may be taking time to gather entropy. In that case you could install > > sys- apps/haveged and add it to your boot run-level. > > Well, I presume the problem is related to ntpdate itself. > > It is working in a blocking way that the remaining boot processes have > to wait until the time got synchronized. Or, until the network is up and a time server can be contacted? > Is there any way to make it update the time in an asynchronize way? > Or should I use ntpd instead? > > Thanks. > > Danny I don't run ntp-client here, but have a look at its startup script and any dependencies defined therein, then perhaps tweak /etc/rc.conf. Does setting rc_depend_strict="NO" makes a difference? -- Regards, Mick signature.asc Description: This is a digitally signed message part.
Re: [gentoo-user] ntp-client slows down the boot process
On 2019-07-26 09:30, Peter Humphrey wrote: > On Friday, 26 July 2019 05:36:29 BST YUE Daian wrote: >> Hi folks, >> >> I use ntp-client to synchronize the date/time of my Gentoo system. >> >> I added it to the default boot level (OpenRC), however it seriously >> slows down the boot process (around 10 seconds or so). >> >> Is there any way to make it faster? Or am I using the wrong service? > > It may be taking time to gather entropy. In that case you could install sys- > apps/haveged and add it to your boot run-level. > > -- > Regards, > Peter. Well, I presume the problem is related to ntpdate itself. It is working in a blocking way that the remaining boot processes have to wait until the time got synchronized. Is there any way to make it update the time in an asynchronize way? Or should I use ntpd instead? Thanks. Danny
Re: [gentoo-user] ntp-client slows down the boot process
On Friday, 26 July 2019 05:36:29 BST YUE Daian wrote: > Hi folks, > > I use ntp-client to synchronize the date/time of my Gentoo system. > > I added it to the default boot level (OpenRC), however it seriously > slows down the boot process (around 10 seconds or so). > > Is there any way to make it faster? Or am I using the wrong service? It may be taking time to gather entropy. In that case you could install sys- apps/haveged and add it to your boot run-level. -- Regards, Peter.
[gentoo-user] ntp-client slows down the boot process
Hi folks, I use ntp-client to synchronize the date/time of my Gentoo system. I added it to the default boot level (OpenRC), however it seriously slows down the boot process (around 10 seconds or so). Is there any way to make it faster? Or am I using the wrong service? Thanks in advance! Danny
