[CentOS-mirror] How often to synchronize mirror?

[Anssi Johansson]

Valeri Galtsev kirjoitti 5.6.2019 klo 18.21:
> Dear All,
> 
> I run public mirror (bay.uchicago.edu), and today I have noticed that 
> the status page
> 
> https://mirror-status.centos.org/
> 
> shows in red it is not in sync for 5 hours, or so. It's been quite some 
> time ago when I first installed it, and that time decent practice was to 
> sync 3 times a day (about once every eight hours). More often was 
> assumed to overwhelm higher tier source.
> 
> What is good practice these days: how often it is OK to synchronize 
> mirror? I changed sync to every other hour (once I notices it shining 
> red on mirror status page). Is that OK, or that will overwhelm higher 
> tier mirror?

My usual recommendation has been every 6 hours (4 times per day). Every 
4 hours (6 times per day) is also OK if more frequent syncs are desired. 
It is also a good idea to pick a random minute to do the sync, so that 
all mirrors would not try to sync at xx:00 (or xx:30 or some other round 
number).

A note about https://mirror-status.centos.org/ -- there are two columns 
that have colourful markers. The first one signifies mirror age, and it 
will turn blue if the mirror's age is between 1d + 4h and 2d + 4h, and 
red if the mirror's age is more than 2d + 4h. If you sync(ed) every 8 
hours, your mirror should not get marked as "red" because of the mirror age.

The other column, which does show some red for your mirror, signifies 
reachability. Most probably your mirror was briefly unavailable today 
for some reason. Everything seems to be OK now, so maybe it was just 
some temporary glitch somewhere.