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

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Why is my ext4 filesystem recognizable only on the machine it was formatted on?

Xubuntu liveCD 11.04 running on "bad machine" with mdadm RAID1 array with an unrecognizable ext4 filesystem: To rescue some files, I installed a new hard drive and formatted it to ext4. I copied ...
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ext4 used space (not -m option, not deleted files)

I'm a bit puzzled about the way ext4 reports used space. On a new Debian wheezy (testing) installation, I consistently got about 1GB extra space used with a 60GB SSD, when compared to du. I then ...
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How to clean journals in ext3/ext4 filesystem? [closed]

Some preamble: I'm taking bitwise copy of disk devices (via dd command) from twin hosts (i.e. with the same virtualized hardware layout and software packages, but with different history of usage). To ...
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zerofree verbose returns what?

zerofree -v /dev/sda1 returned 123642/1860888/3327744. The man page does not explain what those numbers are: http://manpages.ubuntu.com/manpages/natty/man8/zerofree.8.html I found some code on ...
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“unknown partition table” - misconfigured kernel

I was compiling a custom linux kernel for a newly installed machine, and after booting into the new kernel (3.12), the init process fails to find a root device, which I traced to the system getting an ...
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e2fsck giving some error

I am playing with LVM and while doing lvreduce. I now get this error: [root@localhost raja]# e2fsck -f /dev/vg1/lvol2 e2fsck 1.41.12 (17-May-2010) e2fsck: Superblock invalid, trying backup blocks... ...
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How can I dump the contents of a filesystem's superblock?

I understand that I can list the location of a filesystem's superblocks using the following commands. Example First get the device handle for the current directory. $ df -h . Filesystem ...
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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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Ext4 support in Grub 0.9X (legacy) and Grub 1.9X (Grub2)

I'm about to setup my new USB key with Grub or Grub2. In the old days I used ext2 for the boot partition. I'm wondering if I could use ext4 for Grub2? And if use Grub 0.9X, what about support of ...
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jbd2 journal constant i/o

iotop reports a constant i/o about 3% of [jbd2/vda1-8], I think this is the journal manager for ext4. my fstab is: UUID=X / ext4 defaults,noatime,nodiratime 1 1 tmpfs /dev/shm ...
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Backup or snaphot tool for ext4

I'm looking for a backup tool for ext4, which can take a copy from a running FS like /var with no collisions in system after recover such FS. I know BSD dump has an '-L' option, which tells him to ...
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livecd-tools - ext4 errors

I'm using livecd tools to build an ISO image customized to my liking. It appears to build fine, but after booting up, I get a bunch of ext4fs errors indicating referenced inodes were deleted. My ...
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After crash, e2fsck fails with weirdly high block numbers/sizes

After a breaker trip a Raspberry Pi of mine started to halt boot with kernel panic (same message as here). This is a Raspberry Pi running Raspbian, so it runs from a SD card, from a main ext4 ...
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Recovering an ext4 filesystem with corrupt journal

I have a hard drive that seems to have developed some kind of hardware problem in the journal. This prevents the drive from being loaded. Running mount -r -t ext4 /dev/sda5 /mnt/root results in the ...
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Formatting external USB Harddrive ext4

What is the best way to format a non-ssd harddrive with ext4, for as fast as possible usage with a very low performance computer? I mean, options like disabling things (journaling, ...) that slow ...
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fsck ext4 on ssd: max mountcount and checkinterval

I'm using an ssd as the only drive in my laptop (Debian stable). It seems that SuSE sets mountcount to -1, disabling fsck at boot. The thread linked says that ext4 needn't be fsck'd anyway. Is that ...
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Decrease time to shrink ext4 filesystem

I need to shrink a large ext4 volume, and I would like to do it with as little downtime as possible. With the testing I've done so far it looks like it could be unmounted for the resize for up to a ...
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relocate ext4 structures to survive truncation

I have a 6Gb raw disk image with 1 ext4 partition on it. I have only 1Gb worth of data on it Is there a way to reposition/adjust ext4 datastructures such that I can truncate the disk at 1 GB or 1.2Gb ...
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How does my partition (ext4) know its size of used/free space?

I ran df, and the output appears almost instantly: (FS Size Used Avail Use%) /dev/sda1 145G 8.4G 130G 7% sda1 is an ext4 partition. Without summing the size of all files, how can ...
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Disk problems prevent me from booting, or set the disk to read-only. How do I fix the disk?

Problem: Since about one week ago, my Ubuntu system encounters various severe and strange problems. Sometimes the whole system suddenly freezes. I have to push the power button to shut down the ...
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Linux EXT 4: How to list files that occupy a block group?

Linux EXT 4: How to list files that occupy a block group? I believe a file can span multiple block groups. Given a block group, how do i enumerate the paths of all files contained in it?
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What does “mounting fs with errors” mean in dmesg and what to do after that?

I run dmesg and this is what I see: EXT4-fs (sda1): warning: mounting fs with errors, running e2fsck is recommended EXT4-fs (sda1): mounted filesystem with ordered data mode. Opts: Here is the ...
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How can I shrink a LUKS partition, what does `cryptsetup resize` do?

I am in progress of resizing a LUKS encrypted partition that contains a single ext4 filesystem (no LVM or something). The cryptsetup FAQ recommends to remove the old partition and recreate it, but ...
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Are short-lived files flushed to disk?

My program creates many small short-lived files. They are typically deleted within a second after creation. The files are in an ext4 file system backed by a real hard disk. I know that Linux ...
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How to determine how many files are within a directory without counting?

I've been having a fairly serious issue on a high traffic web server. PHP pages are slowing down considerably, and it only seems to be an issue on pages where sessions are accessed, or a certain table ...
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ext4 drive takes forever to ls?

I've had an external HDD formatted in ext4 for a while. For some reason, it's started to take forever to list directories. Sometimes just running ls /mount/point/of/drive takes minutes, sometimes that ...
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How can I change the date modified of a folder to the last changed file inside? [duplicate]

In my media center directory all modified times of my folders are somehow not the desired date. How can I change all modified times of the main folders to the modified time of the newest media-file ...
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How to blacklist bad blocks from a MD-raid + dm-crypt + ext4?

I have a ext4 partition, on top of a dm-crypt, on top of a MD-RAID 10. One partition (/dev/sdc1) dropped out of the array with a ton of read errors. I ran the manufacturer provided diagnostic tool ...
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Which filesystem to backup is the best? [closed]

I just bought a disk to backup all my documents and to store it apart and I don't know what is the filesystem under Linux that gave me better reliability. Maybe I'll backup one time each month and it ...
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How can I recover damaged file from overwritten ext4 partition?

My disk, which was previously ext4 has been formatted and Windows has been installed. I want to recover my previous files (family photos, ..) and I tried everything I could find on the internet. I ...
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is it safe to backup ext4 partition with partimage , which is detected as a ext3 partition

I use partimage to backup my ext4 partition, but during backup, the partition was detected as an ext3 partition. So I'm wondering if this can cause something bad.
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Disk partition emptied during tar backup

This morning I was doing a routine backup of my development drive, one of 4 primary partitions on my hard-drive. The script I ran was: filename="/home/Backups/Devi_"`eval date +%Y%m%d`".tgz" touch ...
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Not possible to recover or delete file in a ext4 filesystem

How can I fix a message like this (read after a dmesg command)? EXT4-fs error (device hdb1): ext4_lookup: deleted inode referenced: 119197 EXT4-fs error (device hdb1): ext4_free_inode: bit already ...
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Recover Linux ext4 partition formatted to hfs+

I have a Linux partition formatted to ext4 and I accidentally formatted it with Mac OS X Disk Utility to HFS+ (Mac OS X Extended Journaled). I tried to recover it with http://www.r-studio.com/ on ...
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Ext4 exhibits unexpected write latency variance vs. ext2

I have a latency sensitive application running on an embedded system, and I'm seeing some discrepancy between writing to a ext4 partition and an ext2 partition on the same physical device. ...
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not able to add files to HDD

I created a single primary partition to my WD WD800BB-55JHA0 80GB HDD using MBR partitioning scheme. Into this partition I created an ext4 file-system with 200048640 inodes! Then I created loads of ...
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How to mount remote file system

I want to mount my Windows NTFS share C:\ to Linux ext4 file system, so I can see the file system tree as part of my Linux file system and transfer my files. PS. I am using rhel6.
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Permissions on an ext4 filesystem on a removable drive used in different machines

I have a USB flash drive with ext4 file system and its files are owned by my user on my local machine, for example by myuser@myhost with 700 permissions. If I unplug my flash drive and plug it in ...
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Recovering files from partition (ext4)

a part of out homework assignment is to recover deleted files from the partition with the ext4 file system. I've tried using the extundelete tool, by following this tutorial. The tool recovered a lot ...
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Risks involved with lazy_itable_init=1 for ext4 fs on SD card

My setup is the following: Linux kernel 2.6.28 e2fsprogs 1.42.7 64 GB class 10 SD card I am attempting to speed up the time it takes to format the entire card to an ext4 filesystem. My research ...
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Extremely long time for an ext4 fsck

The problem that I am having is the extremely long time that fsck is taking. I have thoroughly made searches on Google, but I could not find anything that would resolve the problem. The command that ...
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What is the “cost” of deeply nested folders in ext4?

I was running into performance problems with hundredthousands of files in single directories when I needed to do certain wildcard matches. From my applications point of view, a simple solution is to ...
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ext4: where did my free space go?

I just upgraded my Mageia 2 64bits VM to Mageia 3, and now my virtual disk free space is almost nil, even though less than 100% of the space is used. I am not an ext4 filesystem expert but I have ...
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Safest way to run ext4 fsck on external drive

I have an external drive formatted in ext4 that throws this error message when is plugged in EXT4-fs (sdd2): error count: 8 initial error at 1366215273 last error at 1366215527,it generally works just ...
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What does the command “chattr +c /some/dir/” do?

I'm trying to keep a bunch of plain text files compressed using the extended attribute option - c on a debian ppc64 system. I ran the following commands: # mkfs.ext4 /dev/test/compressed # mount ...
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Convert old /home from ext3 to ext4

I have an old /home partition, that dates back to former linux systems, and it is still in ext3 format. Whereas the rest of my system, / and some other mounted point are devices formated in ext4. I ...
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Encrypted disk filesystem compatibilities

On my Debian Linux system during the install I decided to use disk encryption (the one offered during a regulard Debian install). When the system boots up I need to enter a password and then the ...
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Can the same ext4 disk be mounted from two hosts, one readonly?

I know that mounting the same disk with an ext4 filesystem from two different servers (it's an iSCSI vloume) will likely corrupt data on the disk. My question is will it make any difference if one of ...
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How can I delete data from in a hexdump file from one offset to another?

I've created a disk image which was zeroed, formatted to ext4 file system, and then had several various files copied to it. I'm trying to extract these files using a combination of xxd and dd, but ...
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Is it possible to disable file permissions on a ext3 or ext4 file-system?

Is it possible to disable file permissions on an ext3/4 file-system? Just wondering if it's possible to completely disable or ignore file permissions on a ext3 or ext4 file system. Perhaps a mounting ...