consequences of turning off and on the preallocation

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cabs_14
Posts: 2
Joined: Fri Mar 03, 2017 1:57 pm

consequences of turning off and on the preallocation

Post by cabs_14 » Fri Mar 03, 2017 2:08 pm

Hi!

Here's my situation. I currently have a 2TB drive as my torrent drive and i want to transfer the files on a new 4TB drive. But the problem is the 2TB drive contains about 4.7TB of data. And as i was researching i can across the preallocation feature. I was wondering if i disable preallocation would it "free up" the space on my ongoing torrents? And i could then transfer the "actual data" to the new drive. And after i transfer i would turn preallocation on again.

Would this corrupt my files or give any problems in the future?

thanks!

mike.dld
Transmission Developer
Posts: 283
Joined: Wed Dec 25, 2013 10:56 pm

Re: consequences of turning off and on the preallocation

Post by mike.dld » Fri Mar 03, 2017 2:26 pm

If you have 4.7TB on a 2TB drive, does that mean that you're using sparse preallocation? If so, disabling or enabling preallocation does nothing to files you already have on disk; even if it did, your files would take up more space with preallocation disabled: if file is sparsely allocated, it occupies less space as those parts of it filled with "nothing (yet)" don't count.

Copying the data in a way that considers "holes" might be a better way, e.g. using cp's or rsync's `--sparse` option. Transmission doesn't currently do that for you or else you could've just used its "set location" feature to move data from one drive to another.

cabs_14
Posts: 2
Joined: Fri Mar 03, 2017 1:57 pm

Re: consequences of turning off and on the preallocation

Post by cabs_14 » Fri Mar 03, 2017 5:00 pm

@mike.dld

Hi!

Preallocation is set to 1. Yep i do have a lot of qeued downloads/seeding around 431 in total some are in the range of 100-300GB+

i did plug my torrent drive to a windows machine and would be doing a disk clone to migrate the data. But the clone software refuses to start(meaning not enough free space on the target drive) so i checked the drive propeeties on windows and i found out that it(the torrent drive) has about 4.7TB on it.

Actually one of my concern for not using the "set location" is that im using a raspberry pi 1 model b+ as my tracker.example.com if i do that on that machine it would take days. (As before i had to reverify a few hundred gigs of torrent data and it took 3days to finished.)

And also if i use the "set location" feature will it "set" the preallocated file size aswell? I mean would i still need the 4.7TB free space on the new hdd that i would be migrating the data to?

So would it be better to use the "set location" rather than copy files from the old hdd to the new one?

Sorry im not that accustomed in using transmission/linux that much. As im more of a windows guy. i just started using linux because of the raspberry pi.

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