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Questions tagged [sparsefile]

28 questions
21
votes
1 answer

Why didn't `dd conv=sparse` save space as I expected?

I was going to make an image of my old USB drive. I had good reasons to expect there were some blocks filled with zeros on the device, so to save some space I used conv=sparse option: dd if=/dev/sdb of=myusb.img conv=sparse bs=32M However it saved…
Kamil Maciorowski
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8
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4 answers

copy|move sparse files on NTFS with Windows

How can I copy or move a sparse file from one NTFS volume to another NTFS volume while maintaining the sparseness using the native tools included with Windows? If there is no way to do this with the native tools, then what is a free application…
Michael Yasumoto
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6
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0 answers

Determining status of cloned file on APFS

Apple is now using APFS across several product lines, including macOS. This new filesystem has some nice features for minimizing how much actual disk space is consumed, such as sparse file support and COW clones similar to BSD's clonefile(). I've…
petiepooo
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4
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1 answer

Huge Docker file and `tar` behavior

When I did a backup on my Linux system with tar -czv, I noticed that the process is stuck very long at /var/lib/docker/devicemapper/devicemapper/data (way longer than a copy of all my images and containers should take), while the result file does…
Milleu
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2
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4 answers

How To Format A Disk Image To Be Recognized By MS-DOS?

I'm trying to emulate windows with bochs on my android device. I've got the following drives: an empty disk image to install windows on, a virtual vvfat drive with the setup files, and a cdrom drive with the latest version of DOS. Bochs recognizes…
Jaïr Paalman
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2
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1 answer

Change sparse attribute from an .iso file on Windows 8.1

I have few very large .iso files in my computer altogether about 1TB. All of them are sparse files and i want to remove the sparse flag/attribute from them, is there a way how to do it? Maybe some application or so? I know when i copy the file the…
Ricsie
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2
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1 answer

How to compare huge sparse files efficiently?

There are two sparse files. They are proved identical by diff. But it took 20 minutes (too long time) to compare. I am thinking of taring them into tiny files to speed up the comparison. But they tar into different outputs. They are 512GB huge…
midnite
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1
vote
2 answers

How To Make A Sparse File On Android With Terminal

I'm trying to make a sparse file on android. For this I'm using Android Terminal Emulator. I have installed Busybox so I can use the dd command. Other commands like truncate aren't installed. My question: does anyone know how to make a sparse file…
Jaïr Paalman
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1
vote
1 answer

Looking for the best way to backup and restore a directory of sparse files

We have a directory of sparse files (du returns 240M for one of these files; ls returns 960M). When we copy one of these files over to S3, we end up uploading the entire 960M, and on downloading from S3, du now returns the full 960M. We've tried…
Jedi
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1 answer

NTFS support on Linux, dealing with large sparse files, impact on performance

Background : I attempted to recover data from a failing HDD using ddrescue on a recent Knoppix environment. At first I stored the output to a NTFS partition, but at some point the copying rate became consistently very slow (~600KB/s), and I read on…
GabrielB
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2 answers

ddrescue, “size on disk” lower than total size, with possible impact on performance when writing to NTFS

The backstory is in my previous question and my own answer to it. At one moment I had two partial images created by ddrescue: one file on NTFS filesystem and the other on ext4. I had noticed quite early in the process that the “size on disk” for…
GabrielB
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0
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2 answers

How to remove sparsefile attribute

Answers to how to remove the sparsefile file attribute appear to revolve around: fsutil sparse setflag 0|1 This does not work for me. I am on Windows 7 Pro 32-bit NTFS, as an administrator, using an elevated command prompt. Following the…
EndUzr
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0 answers

Sparse file performance on Windows with an SSD

Does anyone have any data or experience with sparse file performance on SSDs under Windows, with the NTFS filesystem? It seems like performance should be excellent since seek time is effectively zero, but if the filesystem block size does not match…
user237698
0
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1 answer

How to access files on a zfs pool of which only the vdev is left?

I set up a zfs pool mypool with one sparse file as vdev. After a system crash only the undamaged vdev is left. Is there any chance to get files and folders out of it? I don't care to create another pool, currently I would have to force the creation…
Kalle Richter
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0
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1 answer

sparse file moving/copying over NFS

I created a sparse file with truncate -s 4T image.img on an ext4 file system which I mount over NFS. The following test shows that the system has trouble with the recognition of sparse files: both cp --sparse=always /mnt/data_extension/a.img…
Kalle Richter
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