Well, trackers give out the addresses of peers. If those addresses were given out as hostnames, there'd be a lot of DNS work involved, but they don't (as far as I'm aware).
So then the DNS curb would be looking up the hostnames of the trackers, which I'd guess would be under a dozen or so hosts (I don't know, I'm just guessing) per torrent. That seems unlikely to be a hot-spot to the degree that enforcing a long cache would provide a "big boost" to overall performance.
When you have 1000+ torrents seeding 24/7, even the tracker lookups add up. Usually you aren't downloading. Most of the time, torrents stay idle which will make DNS requests a significant portion of the total traffic. Sure, this might seem overkill, but when the VPN is already slowing down things for you, you do whatever needed to shave those seconds.
OpenDNS look up for Google just now took me 500ms, even without the VPN. I use tunnel mode for DNS on the NAS, which can easily double it.
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Well, trackers give out the addresses of peers. If those addresses were given out as hostnames, there'd be a lot of DNS work involved, but they don't (as far as I'm aware).
So then the DNS curb would be looking up the hostnames of the trackers, which I'd guess would be under a dozen or so hosts (I don't know, I'm just guessing) per torrent. That seems unlikely to be a hot-spot to the degree that enforcing a long cache would provide a "big boost" to overall performance.
When you have 1000+ torrents seeding 24/7, even the tracker lookups add up. Usually you aren't downloading. Most of the time, torrents stay idle which will make DNS requests a significant portion of the total traffic. Sure, this might seem overkill, but when the VPN is already slowing down things for you, you do whatever needed to shave those seconds.
OpenDNS look up for Google just now took me 500ms, even without the VPN. I use tunnel mode for DNS on the NAS, which can easily double it.