Clients can race (and go backward), so the more computer answer tends to be to use LWT/CAS to guarantee state if you have a data model where it matters.
-- Jeff Jirsa > On Mar 8, 2018, at 6:18 PM, Dor Laor <[email protected]> wrote: > > While NTP on the servers is important, make sure that you use client > timestamps and > not server. Since the last write wins, the data generator should be the one > setting its timestamp. > >> On Thu, Mar 8, 2018 at 2:12 PM, Ben Slater <[email protected]> >> wrote: >> It is important to make sure you are using the same NTP servers across your >> cluster - we used to see relatively frequent NTP issues across our fleet >> using default/public NTP servers until (back in 2015) we implemented our own >> NTP pool (see https://www.instaclustr.com/apache-cassandra-synchronization/ >> which references some really good and detailed posts from logentries.com on >> the potential issues). >> >> Cheers >> Ben >> >>> On Fri, 9 Mar 2018 at 02:07 Michael Shuler <[email protected]> wrote: >>> As long as your nodes are syncing time using the same method, that >>> should be good. Don't mix daemons, however, since they may sync from >>> different sources. Whether you use ntpd, openntp, ntpsec, chrony isn't >>> really important, since they are all just background daemons to sync the >>> system clock. There is nothing Cassandra-specific. >>> >>> -- >>> Kind regards, >>> Michael >>> >>> On 03/08/2018 04:15 AM, Kyrylo Lebediev wrote: >>> > Hi! >>> > >>> > Recently Amazon announced launch of Amazon Time Sync Service >>> > (https://aws.amazon.com/blogs/aws/keeping-time-with-amazon-time-sync-service/) >>> > and now it's AWS-recommended way for time sync on EC2 instances >>> > (https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/set-time.html). >>> > It's stated there that chrony is faster / more precise than ntpd. >>> > >>> > Nothing to say correct time sync configuration is very important for any >>> > C* setup. >>> > >>> > Does anybody have positive experience using crony, Amazon Time Sync >>> > Service with Cassandra and/or combination of them? >>> > Any concerns regarding chrony + Amazon Time Sync Service + Cassandra? >>> > Are there any chrony best-practices/custom settings for C* setups? >>> > >>> > Thanks, >>> > Kyrill >>> > >>> >>> >>> --------------------------------------------------------------------- >>> To unsubscribe, e-mail: [email protected] >>> For additional commands, e-mail: [email protected] >>> >> -- >> Ben Slater >> Chief Product Officer >> >> >> Read our latest technical blog posts here. >> This email has been sent on behalf of Instaclustr Pty. Limited (Australia) >> and Instaclustr Inc (USA). >> This email and any attachments may contain confidential and legally >> privileged information. If you are not the intended recipient, do not copy >> or disclose its content, but please reply to this email immediately and >> highlight the error to the sender and then immediately delete the message. >
