What does the Availability number tell you?
Availability is a per-torrent score like 0.640 or 37.989. The major number of the Availability tells you how many copies of the least available piece of the torrent you currently see. If the availability is 1 or more, you see all of the pieces of the file(s). If it is 0, you do not see the whole file(s). The decimals are most useful when the Availability is below 1. Lets say availability is 0.652, that means you're only seeing 65.2% of the file.
- Availability reflects your current view to the torrent. It changes constantly based on the seeds & peers you are connected to.
Availability has a direct impact on download speed too. If you are downloading a torrent with good availability, the speed is usually much higher than in a torrent with only one source (as that the upload speed of that source will then limit the whole swarm's download speed). You can also see in the example image that speeds of individual torrents can vary a lot.
You can (and should) easily enable the Availability column: just go to Library tab in Vuze (or the My Torrents tab in Azureus), right-click on the header row where the downloading torrents are queued and choose Column Setup. Enable the Availability column there and hit OK.
Another option to see the Availability is to open the torrent details via right-click > Show Details or doublecklicking on the torrent in the My Torrents view. The Availability is displayed there as a graphic bar and the Availability number itself on the right end of the bar.
Availability shown in the Library view:
- 0.000 means that the Tracker is offline or doesn't track this torrent anymore and DHT can't help either or there simply are no seeds left (old torrent).
- 0.249 means there are only parts of the torrent available (in this case 24.9%). Try to wait for seeds, you might have to wait a day or so. Or it is very new and in Superseeding mode
- 0.640 and all other peers stuck at nearly the same percentage (~64.0% in that case) means the torrent is either stuck because it lacks a seed or there is a very slow seed you're currently not connected to. Be patient, that torrent might finish, very slowly.
- 0.999 (or something below 1 near that) means there is almost 100% of the torrent available. This could be a anti-leech-protection, meaning you just have to wait a few hours or days for it to get 100% of it. If you are already trying to get it for 2 weeks or so read the Torrents stop at 99 percent page.
- 1.000 means that there is currently 100% of the torrent available. You are only able to download this torrent when the seed won't go offline before you got all of it.
- 1.539 and many peers stuck at ~53.9% (check the torrent details) means the swarm is either a bad torrent or the only seed is very slow and everybody is waiting for new data from him, thus you'll reach 53.9% very fast but the remaining 46.1% will take quite some time (could be hours or days) while the original uploader slowly uploads it to peers.
- 3.357 means there are some seeds and peers available and as you see at least 3 copies of each piece, you should be able to download the complete torrent, even if a seed stops seeding.
- 37.989 means that you are downloading a torrent with a big swarm. You see at least 37 copies of all data. If the Average Swarm Speed is not too low you should be able to download it rather fast (partly depending on your upload too).
Important things to note
Note that a good (high) Availability does not necessarily mean that it's a good torrent (and also read about Bad torrents). Another important thing is that seeds are NOT necessary to finish a download since peers can have data to share too, only an Availability above 1 (not counting cases with superseeds). That Availability > 1.0 condition can be also reached with several peers having different pieces of data, so that combined they have all the pieces.
Read the Azureus FAQ