Check Files while downloading (asynchronously)

[jhfry]

I use the check files option to avoid downloading several GB of data just to find that the download is incomplete on the server... an all to common occurrence. However, in its current form, it checks then downloads one file at a time which means that the file checking significantly increases the download time.

The file checks can be quite time consuming, but they don't use much bandwidth. I think it would make sense to give us the option to specify a number of connections per server that can be used for file checks during a download. So if you have 2 servers, each with 20 connections... we could tell Sabnzbd that it can steal 2 per server during a download to use for file checks.

The end result would be that the only checking delay would be for the first download in the queue. Once it's downloading, two connections per server will be used for performing the checks on any subsequent downloads in the queue.. allowing sabnzbd to transition directly into the next download, without waiting on file checking. A far more efficient use of bandwidth, and time.

[shypike]

I don't understand the issue.
SABnzbd already downloads during post-processing.
Extra par2 files for an initially failed post are put in the queue using "Forced" priority.
If not all servers slots are occupied, the next job starts too.

[jhfry]

Try enabling the "Check before download" option on the switches page... then queue two downloads. It will check the first item in the queue then download it, then check the second then download it... that second check is a waste of time... it could have done that during the first download.

[shypike]

Ok, the "check before download" feature isn't very good,
that's why no longer promote it.
You're better of using the feature that aborts or pauses
downloads that can never be successful.

[jhfry]

The check before download feature works fine. I was just suggesting a way to make it more usable.

The abort feature you speak of accomplishes the same thing, but at the cost of consuming bandwidth, potentially a large amount. Because I pay by the GB downloaded, rather than a monthly subscription, I much prefer NOT to download anything unless I have some confidence that it will be complete.

[stomp]

Don't know if that's was suggested but processing while still downloading the same job might be cool. Especially if you have big files. So when the last file is downloaded, there's only this one file left to check. But I suspect it might be hard to implement with par2.exe. This can however be done manually with QuickPAR.

[shypike]

It is not possible to do this with par2cmdline.
QuickPar has two issues: it cannot be controlled by other software and it isn't multi-platform.