...

NOTE: This setting should be sized relative to the size of your disk cache.
Also, it requires clearing the disk cache and restarting ATS to properly take effect.

Cache Threads Per Disk Spindle

My setting here is somewhat of a rough guess. I've had issues in the past with Squid as a web cache
and increasing the threads dedicated to disk access definitely helped. I've noticed setting this value
too low seems to slow down web surfing, while setting it too high slows down other processes on the machine.

CONFIG proxy.config.cache.threads_per_disk INT 16

Maximum Concurrent DNS Queries

The default settings for ATS regarding DNS are set pretty high. I decided for my purposes to lower them,
Your Milage May Vary on these.

CONFIG proxy.config.dns.max_dns_in_flight INT 512

DNS Internet Protocol Preference

I've no idea if this setting really helps or not, but I like to specify my preference for IPv6 over IPv4
as much as possible.

CONFIG proxy.config.hostdb.ip_resolve STRING ipv6;ipv4

DNS Host Cache Database Size

The default settings for ATS regarding DNS are set pretty high. I think the following represents a pretty
good balance between caching too much and caching too little in terms of DNS.

CONFIG proxy.config.hostdb.size INT 8192
CONFIG proxy.config.hostdb.storage_size INT 4194304

Reverse Proxy Settings

As I'm using ATS as purely a forward-only web proxy cache, I decided to turn these off.
I believe the default settings enable ATS as both a forward and reverse cache.

CONFIG proxy.config.reverse_proxy.enabled INT 0
CONFIG proxy.config.url_remap.remap_required INT 0

Miscellaneous Task Threads

Similar to the first setting in this document, the default config for ATS supports up to 2 CPU cores.
I have 4 and decided to update the config to reflect that. One could actually increase this setting higher,
but I'm not a huge fan of Hyperthreading so I didn't bother.

CONFIG proxy.config.task_threads INT 4

Epilogue And Ongoing Problems

Well, that's it! Take a deep breath, restart ATS, and enjoy your new proxy server.

There is one ongoing, lingering problem I'm experiencing that I thought I'd document here.

Once in a while, on Facebook, an image served up by Akamai won't load properly.
I'm assuming ATS errors out on this somehow and thus the browser can't display it.
Reloading the webpage in the browser seems to "fix" the problem but that's really
more of a hack than a solution.

I thought at first that this had to do with somewhat well-known problems regarding
Akamai and the HTTP VARY header, but I've seen it happen with VARY support both
turned on and off.

I plan to look into this further, and will update this Wiki page as necessary.