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]

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1answer
5k views

Why is ext4 only recommended up to 16 TB?

In the ext4 wiki article I've seen that ext4 can be used up to 1 EiB, but is only recommended up to 16 TiB. Why is that the case? Why is XFS recommended for larger file systems? (ELICS: Explain me ...
5
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1answer
2k views

Difference between backup superblocks

Recently I accidentally formatted an EXT4 partition to FAT. I got into a panic. After a long journey through a dark wood in which my hope was fading I could recover my partition and it seems ok. After ...
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0answers
620 views

Corrupt ext4 file system

I have a RAID 1 (hardware) array, where the system crashed, and I removed the hard drives. It is my understanding that a RAID 1 drive should work as an individual drive, as the RAID data is stored at ...
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2answers
2k views

What ext4 functionality does btrfs not support?

btrfs (often pronounced "better fs") has quite a few features that ext4 lacks. However, comparing the functionality of btrfs vs ext4, what is lacking in btrfs?1 In other words, what can I do with ...
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477 views

How do I get ext3/ext4 filesystem features to apply in mke2fs?

As many of you know, ext3/ext4 have filesystem features that make up the special functionalities that they have already, some of these features you can get them from "dumpe2fs", for example this ...
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2answers
1k views

Why is the difference in file size and it's size on disk bigger than 4 KiB?

The ext4 file system usually uses 4 KiB blocks. In this way when you write a small file, and it's size is less that 4 KiB, you will see the difference in any file manager. There are usually two values:...
2
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1answer
3k views

bad geometry: block count 967424 exceeds size of device (415232 blocks)

I am trying to understand what I did wrong with the following mount command. Take the following file from here: http://elinux.org/CI20_Distros#Debian_8_2016-02-02_Beta Simply download the img file ...
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1answer
5k views

Shrink disk image

I have several disk images stored at my fileserver at the moment, these are mainly system images created with dd. The reason for why I have created these images is because I needed the harddrive for ...
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2answers
107 views

File system relatime option

If file system is mounted read only, does relatime option apply? (will it update file access times?)
-4
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1answer
139 views

how i can get ntfs data on ext4 partition?

1] i have installed kali linux on my laptop. but it converted all my hard disk partition into ext4 formate. so my old data on ntfs partition is not showing on ext4 partition. so, how i can get my old ...
4
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0answers
525 views

What is the most recent technique to implement quotas?

Is the quota approach still in use? To limit the usage of disk space and/or the concurrency between users. Quota works with aquota.user files in the concerned directories AND some settings in /etc/...
0
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1answer
53 views

ext4 won't be extended

I manualy installed Debian with encrypted LVM, now I'm trying to extend ext4 from gparted Live, but it won't extend it and I don't understand why for the moment, here are my partitions
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1answer
4k views

Defragmentation options on Ext4 filesystem

I have the following devices with Linux Mint 18.1 on laptops and GNU/Linux Debian 9 on the server. (All are 64-bit and with Cinnamon desktop.) All drive devices are formatted with ext4 filesystem; ...
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3answers
197 views

How can I create files in the directory to have inodes allocated to files with non-sequential inode numbers?

I have mounted an ext4 file system on Dir directory and tweaked some code of directory read which requires having files in the directory inodes with non-sequential inode numbers for its testing. As I ...
1
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1answer
23 views

Data accessible from other systems with the same UID?

Say I've got two dual-boot Linux systems on the same computer. Both share the same /home mount point. Amy, the only user on system 1, has a UID of 1000. She stored some files in /home/amy. Bill, the ...
0
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1answer
592 views

Can't extend root partition with unallocated space [duplicate]

I'm trying to extend my root partition with the unallocated space but it seems like the unallocated space didn't exist. When I reinstalled the system I had two different Free Spaces, one with 32GB and ...
1
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1answer
2k views

I/O error after power failure, filesystem remounting as read-only [closed]

I have a production ESXI server with loads of VMs. I had a power outage a few hours ago that was so long my UPS's battery drained. The automatic shutdown mechanism wasn't working for some reason so ...
0
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1answer
273 views

What does e2fsck do during bootup?

Please assume I'm using a recent version of Debian Linux, on ext4, on a 2 TB Seagate Momentus hard drive, with all the default settings. A) What does e2fsck do during a normal bootup? (And what is ...
3
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2answers
1k views

How to calculate the correct size of a loopback device filesystem image for debootstrap?

I'm using debootstrap to create a rootfs for a device that I want to then write to an image file. To calculate the size needed from my rootfs, I do the following: local SIZE_NEEDED=$(du -sb $...
0
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1answer
740 views

GRUB cannot mount ext4 logical partition

I am trying out different GNU/Linux distributions and I have several partitions on my disk, namely: /dev/sdc1 - primary, 83, ext4 /dev/sdc2 - primary, 83, ext4 /dev/sdc3 - primary, 82, swap /...
25
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3answers
2k views

How to delete a file named “filen/ame” (with slash) on an ext4 filesystem in debugfs?

Playing with e2fsprogs debugfs, by change/accident, a file named filen/ame was created. Obviously the forward slash character / serves as the special separator character in pathnames. Still using ...
1
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1answer
714 views

How to atomically defragment ext4 directories

Fragmentation seems to create a lot of unnecessary seeks when traversing a directory tree on a HDD: # stat -c %F 00 01 02 directory directory directory # filefrag -v 00 01 02 Filesystem type is: ...
0
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1answer
303 views

What does l_i_version in an ext4 inode actually do?

Trying to get behind the internals and secrets related to understanding ext4 I was reading on the ext4.wiki. The author(s) did their best to show the structures used (such as the layout/struct of an ...
3
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2answers
79 views

Can you read an updated mtime, but when reading the contents they have yet to be updated?

Assuming touch etc. is not involved, just standard open, write, close, link system calls. One process is updating files, another is periodically stating to see if they've changed and reloading the ...
12
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1answer
676 views

What could explain this strange sparse file handling of/in tmpfs?

On my ext4 filesystem partition I can run the following code: fs="/mnt/ext4" #create sparse 100M file on ${fs} dd if=/dev/zero \ of=${fs}/sparse100M conv=sparse seek=$((100*2*1024-1)) count=1 2&...
0
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1answer
51 views

Problems on setting up Ubuntu as dual boot

I have one SSD and one HDD on my PC. SSD runs Windows 7, i want to set up Ubuntu as dual boot on the HDD. I downloaded the WUBI.exe for 16.04 and installed it to my HDD. After first startup i got some ...
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0answers
161 views

Is resize2fs the only tool to shrink ext4/3/2 filesystems?

I'd like to adjust the partition layout on my SSD a bit. It looks as all the tools (gparted, etc) rely on resize2fs from e2fsprogs. And resize2fs fails me with a (clearly wrong) message about ...
7
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1answer
5k views

Does umount calls sync to complete any pending writes

We have BBB based custom board with kernel 3.12 running on it. I have doubt regarding umount and & sync. Lets say a script is umounting a partition, Does it require to run sync command before ...
1
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2answers
283 views

When is a file freed in an ext file system?

Introduction Until recently, I thought that on ext file system, inodes have reference counters which count the number of times the file is referenced by a directory entry or a file descriptor. Then, ...
0
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0answers
183 views

How to understand time-dependent file-system check?

When I configure my ext4 file-system to perform a file-system check with 1 day interval, then I can see from the output of dumpe2fs that this has already passed: # date Tue Feb 7 01:15:19 EET 2017 # ...
16
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1answer
2k views

Is there a way to measure the progress of ext4lazyinit?

I had asked a question about ext4lazyinit here. From all I have read and understood, it simply allows you to start using the hdd without creating all the inodes for your file system. The only way ...
1
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2answers
764 views

How to know if ext4lazyinit feature is enabled in your kernel or not?

I would be formatting a newish large capacity 4 TB hdd in few hours. From what little I understand, I could just format it and it will look to be formatted. If I format it in real-time then it would ...
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0answers
114 views

Linux IO Flow - VFS to Block Device [closed]

I'm trying to figure out what is the flow of individual write IO on Linux. I read some articles about the VFS caching (Page, Buffer, iNode, Directory) and also about the EXT3,4 Journaling feature. ...
2
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1answer
3k views

“mounting ext3 file system using the ext4 subsystem” - what does this mean exactly?

I am running Ubuntu 16.04.1, and my main partition is formatted as ext3. Checking syslog I see : mounting ext3 file system using the ext4 subsystem does this mean that the partition is mounted as ext4?...
0
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1answer
827 views

New SSD USB drive: fdisk doesn't change partitions and mkfs doesn't change format

I have this portable SSD drive that I am trying to format for use with my Raspberry Pi 3: https://www.amazon.com/gp/product/B00N0V4JG2 In the past I have used this exact product, but the 128GB ...
2
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2answers
3k views

Mount ext4 read-only

This will still write to /dev/foo if there is a journal: mount -oro /dev/foo /mnt/disk How can I treat /dev/foo as read-only?
0
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1answer
493 views

“xfs_copy” equivalent for ext4?

I love xfs_copy's ability to clone an xfs file system from disk to disk. Is there an equivalent tool to clone an ext4 file system? I've tried dump/restore, but it requires the destination file ...
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0answers
210 views

Clearing reserved space in a luks encrypted volume

I was just checking my LUKS encrypted volume which is mounted the following way. sudo cryptsetup luksOpen /dev/sdd1 z1vol sudo mount /dev/mapper/z1vol /mnt/hdz1/ I discovered that I had a reserved ...
0
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2answers
560 views

Recover specific files from deleted EXT4 partition

Is there any way to recover a few specific files from a deleted EXT4 partition. I deleted all partitions on my 480GB SSD. Afterwards, I created a 200 GB NTFS partition (which is mostly empty) and I ...
1
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1answer
240 views

Any way to be notified of EXT4 errors when mounted with “errors=continue”

I am prototyping a new embedded system that uses ext4 on Flash memory. These systems will be remotely deployed with no local sysadmin, so any diagnostics must also be done remotely via a network. ...
20
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5answers
59k views

Cannot remove file: “Structure needs cleaning”

I have an external hard drive which is encrypted via LUKS. It contains an ext4 fs. I just got an error from rsync for a file which is located on this drive: rsync: readlink_stat("/home/some/dir/...
3
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1answer
729 views

Internal disk failed with bad superblock, how to fix? [closed]

NOTE: The operating system I'm using is on a separate disk (/dev/sdb). I tried to mount my old root partition (/dev/sda12) as usual with the following command: sudo mount /dev/sda12 /mnt However, ...
7
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2answers
791 views

Optimize ext4 for always full operation

Our application writes data to disk as a huge ring buffer (30 to 150TB); writing new files while deleting old files. As such, by definition, the disk is always "near full". The writer process ...
8
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2answers
12k views

fsck won't fsck (unable to set superblock flags)

Following an unclean shutdown on an SD card based device, I took the SD card out to fsck the root filesystem. This led to variations on the following: e2fsck 1.43.1 (08-Jun-2016) /dev/sdc2: ...
4
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1answer
559 views

Recommended maximum percentage to fill a large ext4 data drive

The default reserved blocks percentage for ext filesystems is 5%. On a 4TB data drive this is 200GB which seems excessive to me. Obviously this can be adjusted with tune2fs: tune2fs -m <...
1
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0answers
387 views

ext4 or NTFS lost all files of the last 2 years. How can I recover them?

Problem Suddently, all the files from feb-2015 to nov-2016 have disappeared from the filesystem. Context Over the last 2 years, the system repeatedly terminated abruptly for power-fail reasons or ...
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0answers
338 views

rsyslogd stuck on rotated messages file (and /var/log/messages is empty)

Yesterday /var/log/messages on one server was found empty. Looking into /var/ shows: messages messages-20161125 messages-20161127 But trying to access messages-20161127 hangs the process. tail, ...
1
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1answer
254 views

slow/frozen ext4 // task sync blocked on big mostly write only server

We have several 90TB servers (Areca RAID-6 partitioned into 10 ext4 partitions) The application is basically a ring buffer; continuously writing data and deleting old data. As such, each partition is ...
0
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1answer
143 views

Recover LVM after overwrite with dd

Know that my chances are small (if even there are :(). I have a HDD of 500G with 1 logical volume (ext4). By accident I overwrote it with an ISO of 1,5G: dd if=linuxmint-18-xfce-32bit.iso of=/dev/...
1
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1answer
43 views

Resizing (increasing) primary OS partition

I recently used Clonezilla to move from a very old HDD (160GB) to a new SSD (480gb). Clonezilla did a fine job but it left a lot of empty space unused. I made an attempt to extend the primary OS using ...