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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19 views

Luks and encryption key

I want to check how safe is this solution, I can't find on the web what I have and the differences in scenarios I found make me uneasy especially we are talking about security. What I have is one ...
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mkfs.ext4 not working on 19.1TB logical volume

I can not figure out why its not allowing me to put a filesystem on this logical volume, does anyone have a solution or troubleshoot for this? root@Home-Pi:~# vgs VG #PV #LV #SN Attr ...
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How did my usb change from ext4 to FAT format without me changing it?

I formatted a brand new sandisk usb to ext4 in ubuntu 18.04.2. I have been alternating its use between ubuntu 18.04.3, 64-bit, and debian 10 / armbian, 32-bit. I have been adding files to it until ...
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2answers
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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
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What is the difference between “dentry” and “inode table” in Linux FS? [duplicate]

Are dentries and inode table same thing? If not what is the purpose of each and where are they stored? How does the filesystem exactly work specifically "ext4" or "xfs"?
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Is there any benefit to using ext4 instead of NTFS? [closed]

Trying to copy an 8GB, encrypted image of one of my flash drives (gotten from "dd" command) onto a flash drive, but flash is FAT formatted. So I'll need to format a new flash to transfer it over to. ...
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2answers
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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 ...
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Can you set a file's ctime to min(ctime, mtime) [duplicate]

We know that the mtime of a file can be earlier than the ctime when you make copies of files (or, in my case, move files between file systems without successfully retaining timestamps). I see many ...
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Wrong EXT4 Partition size in luks encrypted partition

I have encrypted my home partition via cryptsetup. Inside the mapper /dev/mapper, i have created a ext4 fs via mkfs.ext4 /dev/mapper/home Now, my home partiotion only has 91 GB. My luks partition ...
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How can I mount filesystems with > 4KB block sizes?

I have a 3TB hard disk pulled out of a WD Mybook Live NAS. The partition table is as follows: Model: ATA WDC WD30EZRS-11J (scsi) Disk /dev/sdb: 3001GB Sector size (logical/physical): 512B/4096B ...
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2answers
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ext4 for external hard drive?

If an external hard drive has been formatted from a certain linux-pc with ext4 file system could it be open on other, different linux-pc or it can be open just on the pc on which it was been formatted?...
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CONFIG_EXT4_ENCRYPTION change in .config not persisting after building the kernel

I'm trying to enable encryption config in the kernel for Nvidia Jetson Nano(Tegra), by using menuconfig and rebuilding the kernel. But the specific change is not persisting and is overridden each time ...
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Filesystem got corrupted overnight

OS: xUbuntu 18.04 LTS. I have my OS installed on 256GB SSD: /boot on ext2 / on ext4 (encrypted) That works fine. I have installed the second 1TB HDD recently for storage and backup. Model: WDC ...
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2answers
49 views

Change filesystem without losing data

I've got 16 nodes of elasticsearch (RHEL 7) - 18TB each, every node has a ext4 filesystem. For better efficency I need to change to XFS filesystem. Is there any tool / way which help me change ...
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How can I make btrfs pretend to be ext4?

Dropbox have just announced that their Linux client will only support ext4 in the future. I currently use Dropbox on a btrfs partition (without any issues). Apparently xattr support is essential. Both ...
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1answer
938 views

How to put syslinux on an sd card

I would like to know how to put syslinux on my sd card and I have tried using extlinux. However, I keep getting the message Missing Operating System. Please help me.
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Ext filesystem: what happens if a journal is replayed after a crash

I read some things about the ext filesystem journaling, including the man pages, but still do not fully grasp the mechanism. What exactly happens with data and metadata when replaying a journal with ...
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Disable and enable ext4 journaling ?

If I disable the journaling function of an EXT4-filesystem using the command tune2fs -O ^has_journal /dev/sda and enable it after the next start, will the data saved on the harddisk remain unaffected ...
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Shutting off power with a non-system r/w ext4 volume mounted

I'm running Raspbian off a read-only ext4 volume. I also have a read/write usb flash volume (ext4, sync) mounted via fstab that runs a simple application that is expected to write occasionally. While ...
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A question on page-management by the virtual file system?

I am trying to get a fairly low level understanding of what happens when a file is opened or changed in linux. Obviously only some of the pages of the entire file, ( i.e. after the blocks on the ...
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directory size inconsistent between “du *” and “du file” [duplicate]

Can someone help me understanding this ? # du -hs * 3,8M depmodwrapper-cross 712M linux-karo 211M u-boot-karo # du --apparent-size -hs * 3,6M depmodwrapper-cross 672M linux-karo 176M ...
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2answers
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What happens if the limit of 4 billion files was exceeded in an ext4 partition?

What happens if the limit of 4 billion files was exceeded in an ext4 partition, with a transfer of 5 billion files for example?
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2answers
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Is it safe to resize partition in ext4?

I would like to reduce the size of an ext4 partition from my disk and I would like to know if it is possible that my files become corrupted during the operation ? I learn that ext4 file system use ...
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extundelete - How to solve 'Block bitmap checksum does not match bitmap when trying to examine filesystem'?

The OS is Ubuntu 17.10 and I've been trying to recover(undelete) with extundelete. (The File System is ext4.) This didn't work. So, I tried with extundelete /dev/mapper/ubuntu--vg-root --restore-...
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Recover accidentally deleted custom files

I accidentally deleted important custom (not known-or-commercial) files from my scientific researches on image processing. I created the files by collecting raw digital signals from an image sensor. ...
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1answer
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How to find orphan directory entries in a ext4 disk

This comes from a long story of trying to recovering a TrueCrypt volume from a hardware failure (thanks, WD). I ended up with an unencrypted 3TB image that had the files that I want to recover. ...
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1answer
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Best parameters for ext4 filesystem to handle virtualbox disk images

I have ext4 partition, which holds disk image files VirtualBox works with. They all are fixed-size images (i.e. files never change their size). They are defragmented as much as possible (with e4defrag)...
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What filesystem metadata operations are actually journaled in ext4 & xfs?

I can't find a simple, straight answer about which filesystem metadata operations are actually persisted to the ext4 & xfs filesystem journals. Note that I am not inquiring about what POSIX ...
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Birth is empty on ext4

I was just reading up on the Birth section of stat and it appears ext4 should support it, but even a file I just created leaves it empty. ~ % touch test ...
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1answer
254 views

How does Linux make sure to reclaim useless “buffers”, from caching the ext4 journal writes, before anything else (e.g. before swapping at all)

My laptop tends to run with about 256MB counted as "Buffers" - in /proc/meminfo and free -w -h - out of about 8GB of RAM. I'm interested in memory usage. I sometimes get into trouble using too much. ...
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SSD partition aligned

I need to prepare the file system of an SSD disk in a way that a Database Administrator pointed me to, which would be a way optimized SSD to work. I have a disk: SSD: Samsung 500 GB SATA III 6Gb/s - ...
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Copying ext4 encrypted files

I'm using ext4 encryption. https://wiki.archlinux.org/index.php/Ext4#Using_file-based_encryption Before I decrypt a directory, I can see lots of encrypted filenames in it. I would like to copy the ...
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3answers
2k views

Share an ext4 filesystem between two RHEL servers, but only one will mount at a time

I have two RHEL 6 servers which share a physical connection to a SAN storage (i.e., so both servers can see this /dev/sdb when running fdisk -l). My goal is not to have both servers access the ext4 ...
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Convert boot filesystem from xfs to ext4

I was wondering if it is possible to convert my boot system from xfs to ext4. If it is possible, how do I do so?
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Problem in Videos playing

I am using Dell Inspiron 3542, when I tried to play videos, it is showing: mpeg-4 AAC decoder not installed. What is the solution? Using PHP 7 on CentOS 64bit.
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1answer
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Renaming a file while it is being written

I'm wondering if this is considered safe. I know the file handles work just fine as long as a link remains, and I know the identifier is the inode rather than the name, but I am not sure how it works ...
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4answers
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Does any file system implement Copy on Write Mechanism for CP

We have seen OS doing Copy on Write optimisation when forking a process. Reason being that most of the times fork is proceeded by exec , so we don't want to incur the cost of page allocations and ...
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64 views

why do some directories have .uuid directory in a directory?

I have seen this quite a few times. In some random directories there is usually a .uuid file or directory therein. The directories are nothing special so as to speak. They are mostly random media ...
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journal_async_commit is not compatible with older kernels. What would you see in this case?

man ext4 mentions a mount option called journal_async_commit. Commit block can be written to disk without waiting for descriptor blocks. If enabled older kernels cannot mount the device. This ...
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What does the 'barrier' mount flag mean in Linux?

The manual for the 'barrier' mount option is: barrier=0 / barrier=1 This disables / enables the use of write barriers in the jbd code.barrier=0 disables, barrier=1 enables (default). This ...
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1answer
47 views

move system partitions to different physical drive with different filesystem

My RHEL7 system is configured like this: Filesystem Size Used Avail Use% Mounted on /dev/mapper/rhel-root 50G 18G 33G 36% / /dev/mapper/rhel-home 504G 147G 357G 30% /home /...
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find extents of each file recursively in a ext4 image file [closed]

I want to log the extents of each file recursively present in a ext4 image file. the physical location of files in ext4 image Any tool i can use for this? or any script? debugfs gives each file ...
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All ext4 files got deleted and the journal can't be found! Is there any way to recover it?

All of the files on my usb stick were deleted by accident (rm -r) but I'm having trouble recovering. When I try to run ext4magic it says "filesystem has no journal" and it mounts as ext2 only. I ...
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2answers
4k views

File type inode/x-corrupted

My system had an unexpected shutdown. Now when I open the file from pcmanfm or nautilus I get file corrupted error. Strangely the files are accessible just fine if I launch pcmanfmas root user. The ...
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Ext4 Error and disk remounted read-only

Sometimes I have an error ext4 and my disk becomes read-only. I can fix it with a reboot and fcsk /dev/sda2 but it keeps coming back... Here are some dmesg : [ 3160.692730] perf: interrupt took too ...
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If a directory is put in lost+found after running fsck, will it contain all of the original contents?

Let's say I have the following directory structure, in an ext4 filesystem: a/b/{1..9} (in other words, a/b/1, a/b/2, ... a/b/9) Suppose I am writing to a/b, and then I lose power. fsck runs and ...
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95 views

Getting sector number from inode or address_space mapping

In am trying to understand how to calculate a sector number from an inode in the ext4 filesystem. Therefore, I am reading ext4_mpage_readpages function. About the function: During a read request, if ...
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any large inode size benefits? (ext4)

From some foggy memories I thought I would "improve" the default settings when creating a Linux partition and increased the inode size to 1024, and also turned on -O bigalloc ("This ext4 feature ...
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Setting noatime via mount options vs no atime updates (A) file attribute

From man chattr When a file with the 'A' attribute set is accessed, its atime record is not modified. This avoids a certain amount of disk I/O for laptop systems. However when I am remounting ...
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How to fix intermittant “No space left on device” errors during mv when device has plenty of space?

Ubuntu 14.04 on a desktop Source Drive: /dev/sda1: 5TB ext4 single drive volume Target Volume: /dev/mapper/archive-lvarchive: raid6 (mdadm) 18TB volume with lvm partition and ext4 There are ...