Yes. When your wallet is locked, your host isn't online, so if your computer restarts and you don't notice right away, you could be saddled with several hours of downtime (or more, depending on how often you check your host computer), and risk losing your collateral for any active contracts you have.

There are three steps involved in making your wallet auto-unlock and getting Sia to start automatically.

1. Save your Sia wallet password in a system environment variable called SIA_WALLET_PASSWORD :
• Linux, Mac, Windows: How do I set an environment variable?
2. Add Sia to your Startup folder so that it starts automatically when you log into your computer:
• Linux: Here is a guide for GUI use on Ubuntu, and Here is a guide for most Linux distros. Add your path to Sia accordingly.
• Mac: Here is a guide to add Startup items. Add Sia accordingly.
• Windows: Here is a guide to add programs to your Startup folder. Add Sia accordingly - you can copy and paste the Sia-UI shortcut from your desktop, or create a shortcut to it. The default install location is C:\Users\<Your Username>\AppData\Local\Programs\Sia-UI\Sia-UI.exe.
3. If you have to enter a username or password to log into your computer, you can set your computer to automatically log in when it starts, otherwise Sia won't start until you log in.
• Linux: Here is a guide to enable automatic login.
• Mac: Here is a guide to enable automatic login.
• Windows: Here is a guide to enable automatic login.

After all of the above steps have been completed, restart your computer and make sure your account logs in automatically, Sia starts, and your wallet is unlocked.

Yes - click on the Terminal (>) icon at the top of the window and enter host announce [address]:9982, replacing [address] with the IP address or DDNS domain you want to announce. Keep the :9982 behind the new IP or address, with no space in between them. This will announce your host using the new address, and incur a small 0.02 SC / "Setup" transaction as a result.

You can also change the default hosting port of 9982, and announce another port if you want to use another - just make sure port forwarding is properly configured for the new port.

There isn't a totally pain-free way to directly migrate Sia data as a host. The best way to do so is to add the new storage folder in the Host tab, wait for it to show as part of the "Total Storage", and then remove the old storage folder. Sia should move any stored data from the old folder to the new folder(s) upon removing the old folder, but this process will take a long time depending on the size of the old folder and Sia will be unresponsive during the move.

It may be easier to resize your old storage folders down incrementally after adding the new folder, which will cause Sia to move data from the old folder to the new folder with each resize. If you do this repeatedly in small pieces (i.e. 50 or 100 GB at at time), Sia is less likely to lock up or crash in the process.

Not easily - this isn't something that's currently officially supported. Some users have attempted it with varying degrees of success using the following steps.

1. Install Sia on the new system, and start it once to generate the internal data files. Then close Sia completely (right click the icon in the system tray and select Quit) - you don't need to wait for it to synchronize or set up your wallet.
2. Open Sia's internal data files (About (i) icon > Open Data Folder) on the old host, then close Sia completely.
3. Move the host storage folders and their contents from the old host to the new host. Obviously, this must be done such that the new storage locations are equal to or larger in size than the old storage locations in order to fit the data.
4. Move all of Sia's internal data files from the old host to the new host. See this FAQ topic if you need help locating them on either the old or new host.
5. In the internal data files on the new host, edit the host\contractmanager\contractmanager.json and host\contractmanager\contractmanager.wal files using a text editor, look for your old storage folder paths, and change them to your corresponding new storage folder paths.
6. Start Sia on the new host and hope for the best.

Sia may take a while to start while it tries to figure out the changes. It may display a message while it does, or it may just sit. Your wallet and host data should be transferred over, though, and hopefully everything will be in order once Sia finishes loading and you unlock your wallet.

The registry is a new feature released in Sia v1.5.1 which supports Skynet and SkyDB, a key-value database which Skynet apps can use to build more dynamic applications on Skynet. It is a lucrative form of hosting because registry data is paid at approximately 250x the rate of your normal host storage.

The registry isn't configured for you by default - you must manually configure it. See our Guide to Hosting on Sia - Step 3 for information on how to configure the registry.

You need to stay online over 95% of the time on average in order to not risk losing a significant amount of collateral. Unfortunately, Sia is biased towards putting the blame on hosts for any sort of downtime, no matter the reason. Because the platform is decentralized, Sia has no way of knowing if you're down temporarily or if you've decided to delete your renter's data and go offline permanently. In a decentralized system, you can't exactly email somebody and say "I'll be back tomorrow!" and they can override the system, as no central authority exists.

Hosting is a big commitment, because you're saying that you'll keep your hosting computer online for the entire contract period. If you're concerned that you won't be able to do that, you might consider other mitigating items like an Uninterruptable Power Supply (UPS) for your computer, or a mirrored hard drive setup to protect against data loss. The alternative, of course, is to not be a host at all. If you have unreliable internet, for example, hosting may not be a great idea.

To find out if your particular configuration is recommended for hosting, visit our Host Tools page.

You can stop accepting new contracts by turning off the green slider next to "Announce Host" in the Host tab. However, this only stops new contracts - you still need to finish out current contracts. Default host settings use a ~26 week contract length and renters use a default ~3 month length, so you should switch new contracts off at least 6 months prior to when you'd like to shut down your host. Otherwise, you may still have contracts active which you could lose collateral for if you take your host offline before they complete.

Once you've switched off new contracts, you can track the progress of any current contracts by typing host into the Terminal (>) at the top of Sia-UI every week or so. Once all collateral is freed (i.e. no collateral shows as locked or risked), you can safely take your host offline. You can also use a tool like the SiaStats Host Monitor by searching for your host's IP address or domain name. While this service doesn't show contract details, once your host's used storage drops to zero all contracts should be completed.

The Sia client maintains additional information on your contracts as a host and your renters' files in an internal location. This information is known as host metadata, and is required in order to provide your renters with access to their data on the Sia cloud storage network. Without it, it's like losing renter data - you'd have no way to know which data belongs to who in your host storage folders. You can see why this data might be important!

For more information on this metadata, including where to locate it and how to back it up, see our Guide to Hosting on Sia - Step 9.

See this FAQ topic regarding unlocking your wallet automatically - it has steps to keep your wallet unlocked and ensure Sia starts when your computer starts or restarts.

Yes - you can use a free Dynamic DNS (DDNS) service. DDNS involves registering for and receiving your own address, like "mysiahost.ddns.net", in combination with running a small program or script on your computer. Some routers also have built-in DDNS support for certain providers. When your public IP address changes, the DDNS program detects the change and configures your DDNS address with the new IP. This way, you can announce your Sia host using your DDNS address, and it should stay Online even with public IP changes.

There are a number of free DDNS providers which can be found by searching for DDNS using your favorite search engine. One popular free option is NoIP.com. Once you have DDNS configured, you can announce your Sia host with your new DDNS address by following the instructions in this FAQ topic.

The most likely scenario is that you don't have Universal Plug and Play (UPnP) available on your network, which automatically forwards required ports for you. To check if Sia's ports are forwarded correctly, open Sia, wait a few minutes, and then visit a site like CanYouSeeMe.org and test ports 9981 through 9984. If you don't get a "Success" message, the ports are blocked and your Sia host will not show as online.

Troubleshooting requires a little bit of work, and basic understanding of router and firewall configuration will be useful. If you're on a work, school, or public network, you may be out of luck because you will likely not have control over the network settings that are required to forward ports. You can check the other steps related to computer firewall settings if you have access to those.

If your port check doesn't come back successful:

1. Visit PortForward.com's Router List and find your router, and then router model in the list. Ignore any ads for their PortForward software or network utilities, unless you're feeling adventurous and also feel like parting with some money. If you don't know your router model, it's usually on a sticker on the bottom or back of the router. Follow all directions, including any regarding a Static IP address, and forward the ports 9981 through 9984 to your hosting computer's IP as instructed.
2. Restart Sia and/or your hosting computer. Use CanYouSeeMe.org again to check the ports. If they're now open and Sia says "Host Online" for more than 5 minues or so, you're all set. If not...
3. Check for any firewall or antivirus software on your computer that might be blocking ports or Sia. For example, Windows has Windows Firewall activated by default. It's impossible to write one single guide for all network security software out there, so we'd suggest doing some Google-Fu for your operating system + opening ports, as well as opening ports through your network security software like Norton if applicable. Remember, the ports you need to open are 9981 through 9984 inbound.
4. Repeat step 2 to test your ports after making adjustments with your firewall and network security software, if applicable.

If the above steps don't fix your problem with blocked ports, your Internet Service Provider (ISP) could also be blocking these ports, though an ISP blocking the ports Sia uses is unlikely. You can try asking for help in the communities listed in our External Links, like Reddit or Discord.

If your original port check came back successful:

Sometimes Sia gets stuck on a stale public IP address, and tries to announce your host under an old IP address if your public IP has changed, which is fairly common with home Internet service. To check this:

1. Visit a site like WhatIsMyIP.com to see what your current public IP address is.
2. Open your \Sia-UI\sia\host\host.json file in your Sia data directory with a text editor and look for a line that says "autoaddress", and compare the IP you found in the previous step with the one listed there. If they're not the same, Sia might be stuck on an old IP address. Try restarting your computer and/or Sia a time or two to see if Sia will pick up on your current IP. You can also try reannouncing your host, or manually announcing your current IP address - see this FAQ topic for instructions.

If your public IP address seems to change often, you might consider using a Dynamic DNS (DDNS) service and announcing your host using that. See this FAQ topic for information on DDNS and how it can help.

Your host needs to be online all the time, and have sufficient resources (i.e. processing power, memory, and Internet bandwidth) to handle being a reliable host on Sia. If any of these get bogged down, Sia may be unable to respond to requests made to your host, and may fail benchmarks as a result. The only way to improve such a situation is to ensure that the hosting system is dedicated to being a Sia host, is on all the time, is reasonably modern, and that you have a decent Internet connection and nothing else on your network is saturating it.

In Sia v1.4.x and v1.5.0, there is a known issue regarding hosts becoming unresponsive for minutes to hours at a time, causing SiaStats Host Monitor benchmark failures and other issues. The SiaStats benchmark failures usually mention an I/O timeout, and several failures may occur in a row. See the topic below for more information.

Your host can become unresponsive if you add or change storage directories - especially on Windows, as Windows preallocates files so adding a drive with several terabytes of space will take as long as it takes to write to the entire drive, which is usually about 2-3 hours per TB. Your host can also become unresponsive during initial startup if it has to process or rebuild certain internal data files, or if it is syncing because it hasn't been online for a while or because the consensus data was removed or bootstrapped.

In Sia v1.4.x and v1.5.0, there is a known issue regarding hosts becoming unresponsive, causing SiaStats Host Monitor benchmark failures and other issues. The SiaStats benchmark failures usually mention an I/O timeout, and several failures may occur in a row. There's not much you can do about this issue currently, but the Sia team is aware of the issue and has attempted a fix for v1.5.1. As this version has just been released in November 2020, it may take a few months to see if the resolution is effective.

Our Host Tools page has network averages for host pricing and suggested starting values for new hosts. You can use these as a rough estimate of what you might be able to earn on Sia. You can also use a website like the SiaStats Host Monitor or SiaHub to view other hosts and see what sort of income they're earning. Once you become a host, the Sia-UI will also provide you with an "expected" income amount for your current contracts. You can also view a breakdown of expected host income by using the Terminal (i) and typing host -v.

In general, hosting is not very profitable because there are many more hosts than there are renters looking to rent space. Additionally, low Siacoin prices mean hosts must charge more in SC in order to make a fiat profit, which is difficult in a competitive marketplace where many hosts are hosting to support the project and not for income. As of March 2021, most hosts earn less than $1 USD/TB/month.

Proof of Burn is a feature to help ensure that hosts cannot perform a Sybil attack. It requires hosts to burn (destroy) a small amount of their income, currently about 4%, to prove they are real. Proof of Burn has not yet been implemented in Sia, but will be in the future.

As you form contracts with renters, your collateral is removed from your wallet in small amounts at a time. This collateral is locked up until the contract is completed, so as a host, you will see a number of transactions removing coins from your wallet. This is expected behavior - in the future, the UI may make this information more user-friendly.

Yes. Type host into the Terminal (>) at the top of Sia-UI, and Sia will tell you how much collateral is locked and how much is risked. Your locked collateral will be returned to you when the related contract expires. If you go offline as a host, you only stand to lose the "risked" collateral. Locked collateral is collateral you put up for the amount of space a renter contracts; risked collateral is what you stand to lose based on the amount of data the renter actually uploads.

Pre-Skynet

Prior to the release of the Sia Skynet, liability was not a very big concern. The core Sia protocol for renting and hosting encrypts a renter's files before they leave the renter's computer, and then breaks files into pieces so that they are distributed across hosts. As a result, hosts received only a portion of an encrypted file. This made liability as a host fairly low, as there was no way for a host to know what type of data they were storing. Data could also not be shared with others by a renter, so only the renter could download their data with their own Sia installation and their seed, limiting the chance that the data would be discovered by a third party.

Post-Skynet

With Skynet and Sia v1.4.3+, this has changed. Skynet uses normal Sia hosts for storing files, but stores files in one piece and unencrypted. Hosts have less plausible deniability about the possibility of holding illegal data - while it is difficult to view the data you store as a host, it is not impossible to inspect your hosting blob files. Additionally, Skynet uploads are public and designed to be shared, so there is a high chance that illegal data may be discovered by a third party. There are significant concerns regarding host liability with Skynet uploads for this reason, as an argument might be made that if it is technically possible as a host to view the data you store, you are responsible for rejecting illegal material.

Additionally, even as a traditional Sia host, it is possible for renters to configure their client such that they store data unencrypted and in one piece similar to Skynet - so either way, as a host you run the risk of holding illegal material in one unencrypted piece, and the potential for liability related to doing so.

Laws and regulations vary by country as to a traditional service provider (i.e. a web host) and their liability for storing illegal data. Generally, the law is such that hosts are not liable for what renters upload, but if they are made aware that they are providing access to something illegal (i.e. copyright infringing or otherwise), they must disable access to the content. This is difficult as a Sia host, as there is no easy way to manage the contents of your host data. As such, you may be subject to takedown requests which you cannot fulfill without taking your host offline entirely and losing any collateral associated with all your contracts.

You should consider the above carefully before committing to becoming a Sia host, and consult with a laywer or other legal counsel if you are concerned about the liability of becoming a host.

Takedown requests may be difficult to deal with as a Sia host for two reasons.

First, there is no easy way to access the data you store as a Sia host. This data is stored in a blob file, with no simple way to view its contents or discern between file pieces and what belongs to who. Data from traditional Sia renters is also encrypted and broken into pieces, further complicating your potential search. While Sia provides a small command line option to remove a particular sector from your hosting blob, you would need a way to determine which sector you need to remove. This information is avalable in the Sia metadata of the renter which owns the file, and without being given this information from law enforcement or another party, it is likely impossible to determine how to remove a particular file on your own.

Second, with the introduction of Skynet in Sia v1.4.3, there are additional complications which make a takedown request more likely:

• Skynet files are stored unencrypted and whole on normal Sia hosts
• These files are still mixed into the host file blob with no easy way to inspect them
• Skynet files are publicly accessible and can be shared through public Skynet Portals, so the chance of an illegal file being discovered by a third party such as law enforcement is much higher
• Currently, there is no way for normal Sia hosts to decline to accept Skynet files

In practice, if you receive a takedown request as a host, you would likely need to take your entire host offline because you would be unable to easily remove access to only the offending content. You would then lose any potential hosting income, as well as your collateral, for all data you stored as a host. For this reason, hosting is currently a risky proposition.

If you are given sector information with a takedown request, see the FAQ topic below for information on how to remove a sector from your host data.

To remove data from your Sia host, you need to know the sector it resides in. If you receive a takedown request or you somehow determine you hold objectionable material as a Sia host, and you don't know which sector you need to remove, you may be out of luck - see the FAQ topic above for an explanation on why locating particular content in your Sia host data is basically an impossible task.

If you are fortunate enough to be given sector information as part of a takedown request, or you somehow discover a sector with objectionable material yourself, you can use the Sia-UI Terminal command host sector delete [sector], replacing [sector] with the appropriate sector to delete.

Note that even though storing illegal data and being required to take it down isn't necessarily your fault, you will likely lose the collateral and hosting income for the deleted data/sectors - as Sia will see the sector deletion as a loss of the renter's data. Sia as a protocol doesn't care why the data is gone, only that you don't have it and were unable to fulfill the contract of storing the data as a host for the required amount of time.