[HN Gopher] Patterns of Distributed Systems
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       Patterns of Distributed Systems
        
       Author : eclectic29
       Score  : 99 points
       Date   : 2023-06-27 16:43 UTC (6 hours ago)
        
 (HTM) web link (martinfowler.com)
 (TXT) w3m dump (martinfowler.com)
        
       | nijave wrote:
       | https://microservices.io/patterns/index.html has some patterns as
       | well that aren't necessarily specific to a microservice
       | architecture.
        
       | withinboredom wrote:
       | > The main reason we can not use system clocks is that system
       | clocks across servers are not guaranteed to be synchronized.
       | 
       | Sentences like this will make me never regret to moving my
       | infrastructure to bare-metal. My clocks are synchronized down to
       | several nano-seconds, with leap-second skew and all kinds of
       | shiny things. It literally took a day to set up and a blessing
       | from an ISP in the same datacenter to use their clock sources
       | (GPS + PTP). All the other servers are synchronized to that one
       | via Chrony.
        
         | slt2021 wrote:
         | I never understood why "The main reason we can not use system
         | clocks is that system clocks across servers are not guaranteed
         | to be synchronized." is considered True even with working NTP
         | synchronization?
        
           | withinboredom wrote:
           | A few milliseconds difference can mean all the difference in
           | the world at high enough throughput (which is about the best
           | you can get with NTP). When you can control the networking
           | cards and time sources, you can get it within a few
           | nanoseconds across an entire datacenter, with monitoring to
           | drain the node if clock skew gets too high.
        
         | antonvs wrote:
         | It's not just about bare metal or not. The sort of distributed
         | systems these patterns apply to are not small local clusters in
         | a single datacenter.
        
           | codemac wrote:
           | And the really big ones do much more epic clock management,
           | and keep things wildly in sync across the globe. See the
           | recent work with PTP that fb and others are trying to do
           | openly. Google and others have their own internal
           | implementations.
        
           | withinboredom wrote:
           | In the cloud, you have very little control over the clocks.
           | If you have baremetal, there's almost always the ability to
           | configure (at least) GPS time sync for a server or two. If
           | you get to the point where you have entire datacenters,
           | there's no excuse NOT to invest in getting good clocks -- and
           | is likely a requirement.
        
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       (page generated 2023-06-27 23:00 UTC)