DNS

I setup 4 DNS servers on Monday using RamNode and BuyVM, and have been monitoring the performance of them since then. I am running PowerDNS with MySQL backends, replicated from the Atlanta node to all other nodes using MySQL master-slave replication. Additionally, the Atlanta node is running Poweradmin.

The physical node configurations are as follows:

RamNode – Atlanta
512MB RAM
2 CPU Cores – 3.3Ghz
20GB SSD

RamNode – Seattle and Netherlands
256MB RAM
1 CPU Core – 3.3Ghz
10GB SSD

BuyVM – Las Vegas
256MB RAM
2 CPU Cores – 2Ghz
30GB Disk (non-SSD)

Monitoring results from the last 24 hours on each node from another node in RamNode’s Seattle location:

RamNode – Atlanta

dns_ramnode_atlanta

RamNode – Seattle

dns_ramnode_seattle

RamNode – Netherlands

dns_ramnode_netherlands

BuyVM – Las Vegas

dns_buyvm_lasvegas

The RamNode nodes are rather consistent, short of usually small spikes every hour or so. The BuyVM response times vary widely, however; more than I was expecting. To show just how much the responses are varying, here is a 4-hour capture of the response times:

dns_buyvm_lasvegas_4hours

I haven’t looked into why the BuyVM node is performing worse than the RamNode nodes, however I suspect it has something to do with the fact that it has a lower clock speed and its disks are non-SSDs versus the RamNode SSDs.

Update: I moved the BuyVM DNS node to DotVPS’s UK location, and it is performing much better than the BuyVM node. Here is the configuration for that node:

DotVPS – UK
512MB RAM
1 CPU Core – 2.27Ghz
25GB Disk (non-SSD)

And the performance graph for that node:

DotVPS – UK

dns_dotvps_uk

So I’m still not sure what the issue is with BuyVM. It still very sporadic up until I turned off that node. Maybe their upgrade to SSDs will fix them, however I’m not sticking around to find out.

Update: DotVPS is no longer in business and therefore links have been removed.

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