Questions tagged [fallocate-command]

Use this tag for the fallocate command, NOT fallocate system call.

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What are the holes in files created with fallocate?

If we create a swapfile with fallocate we are told that the file contains holes and therefore the operation is halted. What are these holes? Is it unallocated disk space, which makes the whole file ...
2
votes
2answers
599 views

Can losetup be made efficient with sparse files?

So my setup is like this. $ truncate -s 1T volume $ losetup -f --show volume /dev/loop0 $ mkfs.ext4 /dev/loop0 $ ls -sh volume 1.1G volume $ mount /dev/loop0 /mnt/loop Now I have a 1.1TB volume, as ...
1
vote
1answer
288 views

Is it possible to zero the free space on a LUKS volume?

I want to have a LUKS volume as a loopback device pointing at a sparse file. Lets say I put a 20gb file on it, then later I delete it. How can I zero that area on the device itself so I can fallocate -...
0
votes
1answer
283 views

Why dd speed decrease significantly after fallocate once

Why fallocate -c -l1GiB once cause the second loop of dd speed decrease from 1.0 GB to ~200 MB/s ? xb@dnxb:~/Downloads/test$ fallocate -l 10.2GiB lala.mp4 xb@dnxb:~/Downloads/test$ ls -larthiF --...
6
votes
2answers
2k views

What is the difference between `fallocate --dig-holes` and `fallocate --punch-hole` in Linux?

I totally understand that --dig-holes creates a sparse file in-place. That is, if the file has holes --dig-holes options removes those holes: Let's take it in a very simplified way, let's say we ...