Add hosting guidelines

res/include/md/about.md

@@ -38,6 +38,33 @@ spare some coins. Possible methods for donating are:
    href="https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=WU49A5NHPAZ9G&source=url">
    Donate with PayPal</a>
 
+## How does pixeldrain store files?
+
+Pixeldrain uses a few different techniques to store files cheaply, efficiently
+and performantly. The servers which accept files from users have a hard disk
+drive cache of typically a few terabytes (4 to 16). This is where most of the
+files are kept. When a file is requested from another server it will look up
+where the file is stored using a lookup table in the shared database. It will
+then try to contact that server to request the file and proxy the data directly
+to the requesting user.
+
+Each server keeps track of which files are popular with its own userbase. This
+includes files which it is not storing locally. It does this using a popularity
+score. Every time a request to read a file comes in it will add 1 to the score
+of that file. This score will slowly degrade over time. Periodically the server
+will request all files with a high popularity score so it can store them locally
+to save bandwidth. If there is not enough space available to store these popular
+files it will move some less popular files to the next storage medium to make
+space available for the more popular files.
+
+The next storage medium is Sia. This is where all the files live which are not
+requested frequently, but are still occasionally needed. Sia is a storage
+marketplace where anyone can sell their storage space for financial compensation
+in Siacoins. If you have storage space available and would like to provide it to
+pixeldrain and other services you should read our [Sia hosting
+guidelines](/hosting). There we explain which requirements we are setting for
+hosts and some handy tips for getting started with hosting.
+
 ## Do I need to register an account?
 
 Not if you don't want to. You're free to use pixeldrain completely anonymously.

res/include/md/hosting.md

@@ -0,0 +1,119 @@
+# Sia hosting guidelines
+
+Pixeldrain uses [Sia](https://sia.tech) to offload files which are not requested
+often, but still need to be kept. Sia is a free storage market where any host
+can choose their own pricing. Because of this the users of the network need to
+be careful when choosing the hosts to make contracts with.
+
+Because pixeldrain is fairly cost-constrained we are forced to set some hard
+requirements on storage and bandwidth pricing for Sia hosts.
+
+## Rates
+
+We will only make contracts with hosts that fullfill all these requirements.
+Keep in mind that these are maximums, you are allowed to go lower.
+
+| Requirement              | Max rate       |
+|--------------------------|----------------|
+| Contract formation price | €0.001         |
+| Storage price per month  | €2.00 / TB     |
+| Download price           | €1.00 / TB     |
+| Upload price             | €0.50 / TB     |
+| RPC price                | €0.0001        |
+| Sector access price      | €0.0001        |
+| Collateral per month     | €6.00 / TB     |
+
+This may seem low, but keep in mind that these prices are before redundancy. We
+have to upload all our data three times to the Sia network in order to reach
+high availability. If you multiply everything by three it becomes much more
+reasonable.
+
+Other settings we pay attention to:
+
+| Setting               | Recommended value |
+|-----------------------|-------------------|
+| Max contract duration | At least 3 months |
+| Proof window duration | 1 day             |
+| Download batch size   | At least 16 MiB   |
+| Revision batch size   | At least 16 MiB   |
+
+## Tips and tricks for becoming a better host
+
+### Use a stable Linux or BSD-based operating system
+
+Sia is known to run better on Linux or BSD based operating systems. Windows is
+discouraged due to I/O reliability issues. Windows often sacrifices reliability
+for better performance, because of this crashes are more common on Windows and
+also have a greater chance of resulting is data loss. Forced updates and other
+interruping system processes are also likely to harm hosting uptime and
+performance.
+
+We can recommend Debian, CentOS or Ubuntu LTS for hosting. These are systems
+which are known to be able to run uninterruped for decades at a time. They are
+also regularly patched with security updates which don't even require restarting
+most of the time. This makes these systems perfect for the role of hosting on
+Sia.
+
+### Enable TCP BBR and other network stack optimizations
+
+BBR is a new congestion control agorithm which dramatically decreases the time
+needed for a TCP connection to ramp up to maximum speed. It also contains
+improvements to counter other problems like router buffer bloat which causes
+network latency spikes. Here's an [in-depth analysis of the benefits of enabling
+BBR](https://blog.apnic.net/2017/05/09/bbr-new-kid-tcp-block/).
+
+To enable BBR you need yo have kernel version 4.9 or higher. See your kernel
+version with `uname -a`. On Ubuntu you can upgrade to a newer kernel by
+[enabling HWE](https://wiki.ubuntu.com/Kernel/LTSEnablementStack).
+
+Create a file called `/etc/sysctl.d/60-bbr.conf` with the following contents:
+
+```
+net.core.default_qdisc = fq_codel
+net.ipv4.tcp_congestion_control = bbr
+net.ipv4.tcp_notsent_lowat = 16384
+net.ipv4.tcp_slow_start_after_idle = 0
+```
+
+After doing that you can run `sysctl -p` or reboot to apply the changes. Verify
+that it's working with this command: `sysctl net.ipv4.tcp_congestion_control`.
+It should return `bbr`.
+
+Here's a more in-depth [guide to the configuration of the linux network
+stack](https://www.cyberciti.biz/cloud-computing/increase-your-linux-server-internet-speed-with-tcp-bbr-congestion-control/).
+
+### Use Sia Host Manager to configure your host
+
+SiaCentral's [Host Manager](https://siacentral.com/host-manager) is a great tool
+for monitoring and configuring your host. It explains all the settings in
+detail, gives an option to set prices in any currency you like and gives
+detailed insights into your contracts and revenue stream.
+
+### Sign up for SiaStats host alerts
+
+When your host is configured properly SiaStats will monitor its uptime and
+performance. These stats are important for renters to discover good hosts and to
+get an overview into the state of the hosting network.
+
+If your host has been online for a while it will show up on SiaStats' [hosting
+page](https://siastats.info/hosts). If you search for your host there will be an
+option to sign up for hosting alerts.
+
+### IPv6 capability is encouraged
+
+Pixeldrain makes heavy use of IPv6 across its systems. We do this because we
+believe that IPv6 is a critical component for the free internet. The old IPv4
+requires terrible hacks like NAT to work at a large scale. IPv4 addresses are
+also scarce and expensive to rent. All this money is thrown away on a legacy
+system for which a replacement has already existed for over a decade. NAT limits
+the growth of peer-to-peer software by making it impossible for applications to
+communicate freely over the internet. Instead we need to add more hacks on top
+like port forwarding to make it work. This has harmed the growth of the open
+internet a lot over the decades and will harm it more if we keep going like
+this.
+
+So enable IPv6. If you don't have IPv6, call your ISP and ask them why not.
+
+<div style="margin-top: 100px; height: 128px; text-align: center;">
+<a href="https://sia.tech/">{{ template "built-with-Sia-mono.svg" . }}</a>
+</div>

res/include/style/layout.css

@@ -298,7 +298,11 @@ a:hover {
 	text-align: left;
 	max-width: 40em;
 }
-table:not(.form) {border-collapse: collapse; width: 100%;}
+table:not(.form) {
+	border-collapse: collapse;
+	width: 100%;
+	margin: 14px;
+}
 tr:not(.form)    {border-bottom: 1px var(--layer_2_color_border) solid;}
 tr > td, tr > th {padding: 0.3em;}
 @media(max-width: 30em) {
@@ -312,7 +316,7 @@ tr > td, tr > th {padding: 0.3em;}
 }
 
 pre {
-	padding: 2px;
+	margin: 16px;
 	border-bottom: 1px var(--layer_2_color_border) solid;
 	overflow-x: auto;
 }

webcontroller/file_viewer.go

@@ -43,10 +43,8 @@ func adType() (i int) {
 	switch i {
 	case 0, 1, 2, 3: // 50% of the traffic
 		return 1
-	case 4:
+	case 4, 5, 6, 7: // 50%
-		return 2 // 12.5%
+		return 2
-	case 5, 6, 7:
-		return 0 // 37.5%
 	default:
 		panic(fmt.Errorf(
 			"random number generator returned unrecognised number: %d", i),
@@ -160,6 +158,7 @@ func (wc *WebController) serveFileViewerDemo(w http.ResponseWriter, r *http.Requ
 			"description":    "A file to demonstrate the viewer page",
 			"mime_image":     "/res/img/mime/text.png",
 			"thumbnail":      "/res/img/mime/text.png",
+			"abuse_type":     "",
 		},
 	}
 	err := wc.templates.Get().ExecuteTemplate(w, "file_viewer", templateData)

webcontroller/web_controller.go

@@ -115,6 +115,7 @@ func New(
 		{GET, "widgets" /*      */, wc.serveTemplate("widgets", false)},
 		{GET, "about" /*        */, wc.serveMarkdown("about.md", false)},
 		{GET, "appearance" /*   */, wc.serveTemplate("appearance", false)},
+		{GET, "hosting" /*      */, wc.serveMarkdown("hosting.md", false)},
 
 		// User account pages
 		{GET, "register" /*        */, wc.serveForm(wc.registerForm, false)},