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Questions tagged [ext4]

ext4 (fourth extended filesystem) is a journalling file system for Linux, developed as the successor to ext3. Use this tag for question that are ext4 specific, generic file system related questions should use tag [filesystem]

ext4 (fourth extended filesystem) is a journalling file system for Linux, developed as the successor to ext3.

Ext4 information on wikipedia includes hostoric information.

Ext4 is supported on Windows and OSX by commercial software.

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Is data=journal safer for Ext4 as opposed to data=ordered?

The default journal mode for Ext4 is data=ordered, which, per the documentation, means that "All data are forced directly out to the main file system prior to its metadata being committed to the journal." However, there is also the data=journal…
Tim
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Why doesn't my exactly 100 MiB partition at 1 KiB block size have the corresponding available blocks/space?

I have a very high density virtualized environment with containers, so I'm trying to make each container really small. "Really small" means 87 MB on base Ubuntu 14.04 (Trusty Tahr) without breaking up the package manager compatibility. So I use LVM…
maniaque
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Unable to delete file "ldlinux.sys" from a partition

I wanted to create live bootable USB of gparted via unetbootin. But by mistake I specified the device of USB as a partition of external HDD rather than the USB drive. I deleted all the files that unetbootin created in that HDD partition except one…
Ravi
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How can I find the last sector used by an ext4 filesystem?

I need to identify the last sector used by an ext4 filesystem so that I can move it to another device. The filesystem has been shrunk (with resize2fs) and is smaller than the partition that contains it, so I am not asking how to find the last sector…
starfry
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Is it safe to use sudo tune2fs -m 1 /dev/sda1?

My external 5 TB backup drive is almost full. When I formatted it as Ext4 and created just one partition to it using Raspberry Buster, it reserved 10 % of space so available space was just 4.5 TB. If I run sudo tune2fs -m 1 /dev/sda1, does it erase…
driveworries
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Journal has aborted ext4

Hi in my CentOS guest in VirtualBox I just realized, that my FS is mounted as readonly. From dmesg I got: [ 1725.767566] EXT4-fs error (device sda1) in ext4_ext_remove_space:3028: Journal has aborted [ 1725.767736] EXT4-fs error (device sda1) in…
Betlista
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ext4 - An entire directory disappeared?

Okay, this has me totally stumped. Background: I'm working on a cryptanalysis homework, trying to break a vigenere cipher with a 26 character key (a shuffled alphabet). Even though there are some 403 septillion possible keys, I tried a naive brute…
Harrison Pickett
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Can I mount half an ext4 partition

I had a hardware raid array, a disk failed during migration and the controller flipped out and is unable to recover. I've written a small python script which has correctly mapped out the state of the array as it is currently (about 160GB was…
user999305
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Are there downsides to enabling the "inline data" feature of EXT4?

I just read about the "inline data" feature in EXT4, and more specifically about that answer on how to enable it. What are the reasons why this feature isn't enabled by default in EXT4 ? I guess it's to keep the FS compatible with older kernels,…
ChennyStar
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Do files in an ext4 filesystem allow constant time seeking?

I'm working with Tensorflow's TFRecords format, which serializes a bunch of data points into a single big file. Typical values here would be 10KB per data point, 10,000 data points per big file, and a big file around 100MB. TFRecords are typically…
Yaoshiang
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How many files in a directory before the size of the directory file increase

In Linux or more particular EXT4 the initial size of directory file is 4kB. But if a large enough number of files are stored within the directory the size of the directory file will increase due to the increase of the internal "file list". However,…
Lars Nielsen
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ext4 inodes in use for files that are missing

Executive summary: Every tool I've tried confirms lots of inodes in use on this ext4 partition Every tool I've tried shows me that there are no files on the partition It's not files held open and it's not an overlay mount Long story: I have an…
Kisama
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ext4 flags to specify "extents" mode?

I've formatted a new filesystem with and without extents feature just to understand how this feature works. However, when I look at the inode field i_flags I see that this field always has zero value (for "used" inodes 2, 7 and 11). Documentation…
HEKTO
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In EXT4, are "extent" and "block group" the same thing?

TLDR; In EXT4 terminology, are "block groups" and "extents" the same thing ? [EDIT] The suggested What do "extents" feature do in ext4 filesystem in linux? discussion doesn't answer that question. While it explains clearly what "extents" are, it…
ChennyStar
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32-bit block addresses in ext4 inode struct

In the Linux kernel source, the block numbers in an on-disk inode struct are 32-bit. Why? Surely Linux can support more than 2^32 blocks...
extremeaxe5
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