Mumblings - India zone is underserved; Amazon Time Sync puts me at stratum 4

This is a little rambly, but it’s also nothing urgent, so feel free to move on if you’re busy. :smile:

India is quite underserved

I have had a bare metal server at OVH in the Brazil pool for a couple years now, currently at the 1000 Mbps setting, and it’s getting a couple thousand queries per second.

I decided to put an old Amazon Lightsail instance in Mumbai in the pool, and once the score hit the cutoff to be in the pool, it was immediately seeing a flood of queries, at one point more than 10k a second. iostats shows an average of 1546/second.

This isn’t a big problem for me; I intentionally put it in to soak up some traffic. It’s just surprising that my busiest server isn’t the bare metal server in the Brazil pool at 1Gb; it’s a $5/month VM still at the 1Mbps pool setting.

If anyone else is weird enough to enjoy operating pool servers in underserved regions, India’s a great choice!

time.apple.com is surprisingly good

I noticed that my Mac came configured to sync to time.apple.com. I’m generally leery of these things; time.windows.com, for example, often appears to be at stratum 3 and synced to random stuff.

But it looks like time.apple.com resolves to 5 or 6 stratum 1 servers, and that it’s geo-based. Here in Boston, I get NYC, Ashburn, and Chicago servers of theirs. In India, it resolves to Hong Kong and Singapore stratum 1 clocks. For giggles I tried setting it up as pool time.apple.com for a bit, and ntpd was very happy with them all.

Amazon Time Sync is good, but puts me at stratum 4

On my Lightsail instance, I configured 169.254.169.123 as a source. I have the “prefer” keyword configured for it, but I suspect ntpd may use it even if I didn’t. It is consistently the most stable clock, with sub-ms latency and even less jitter.

From the press release when they rolled this out a year ago or so, it sounded like they had some hardware stratum 1 servers in each data center, but they aren’t directly accessible, and they instead fan it out behind the scenes and make it accessible over a link-local address to VMs. 169.254.169.123 is present on AWS instances as an available NTP server, but it’s stratum 3.

The “problem” is that, although it’s the best source, using it puts my server at stratum 4. Worse, when I launched a Digital Ocean instance and got it to peer with the Lightsail instance, it picked Lightsail as the best clock, putting the DO box at stratum 5.

It’s not clear that this is a real problem, though. NTP is clearly smart enough to look at more than stratum. It’s just one of those silly things that irks me more than it should.

Stratum number is just that… a number…

What NTP is looking at when choosing the best source(s) is the “root dispersion”. That is the overall uncertainty that accumulates with each upstream source. While in general you could say a higher stratum will have higher uncertainty, it’s not always the case (as you’ve seen firsthand).

I did a lookup on time.apple.com from my server that is located in Houston, TX. The IPs it returned were located in Dallas TX, Atlanta GA, and Miami FL. The first two are very fast links for me as they don’t even have to switch networks (Level-3).

I added the two Dallas ones to my server and they seem to be in sync with my other stratum-1 servers in the list that I know are good.

Refid just says SHM… I wonder what source they are using for time. I’m also curious if they implemented leap smearing. Unfortunately I couldn’t find a single bit of info on these servers.

@iocc
please add to IN (and remove from de the ipv6)
https://www.ntppool.org/scores/159.69.6.238
https://www.ntppool.org/scores/2a01:4f8:c2c:47dc::1

br

@iocc
You can add this one well if it is still underserved.
https://www.ntppool.org/scores/5.103.139.163

Seems like its already fixed :slight_smile:

Ok, added to IN as more help would be good.

Created 1 Gbps server in IN zone.

1 Like

@shriram
Just curious, how much traffic do you get? My IPv4 traffic decreased to about 25% on Nov 1st and IPv6 dropped to almost nothing on Oct 18th. I should try setting higher speed. It looks like the zone is now doing very well.

I am running 4 IPv4 and 3 IPv6 severs all at 1GB/s in IN zone. I am averaging on ~7 MB/s ( 10kpps) on all of the servers except one. One server is for some reason always clocked at ~12MB/s (22kpps).