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

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A weird issue relate to ext4/lvm/raid-5 after partition recovery

I have 3 hard disks, in the following paragraphs named /dev/sda, /dev/sdb and /dev/sdc, newest came first. Note: /dev/sdc has one primary partition /dev/sdc1, one extended partition /dev/sd2, and 3 ...
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99 views

Unable to Create Files In Directory

There are lot of these kinds of questions on superuser, so I'll try and keep this quick by telling you what it's not: There is no application involved here. Just a user and a filesystem. I can login ...
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78 views

Recover LVM with software raid

I have a Synology NAS using SHR mode, which is basically LVM and Raid 5. Somehow my LVM volume became corrupted and won't mount anymore. This volume houses over 20TB of data, and most of it is NOT ...
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150 views

ext4 superblock backup locations are different from what is documented

When I format an ext4 filesystem the mkfs says: Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 4096000 My sparse_super flag is ...
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28 views

EXT and other filesystems

Is it true only NTFS needs to be defragmented? Are filesystems like ext4, 3 and 2 immune to fragmentation issues. Apple never seems to require a defragmentation so what makes some filesystems immune ...
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544 views

On Linux allow a file to be read/write but not deleted

Is there a way in Linux on a ext4 file system that I can make a file readable and writeable but not deletable? The directory that the file resides in still needs to be writeable by the owner of the ...
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38 views

How to safely shred unlinked files on a Unix-based file system?

Scenario: After working with a confidential file (e.g. PDF a bank statement), you typed: rm my-confidential-file (or the famous Shift-Delete action in a GUI-based file browser such as nautilus) ...
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253 views

Why I cannot format a microSD to ext4?

I have a Toshiba Class 10 64GB microSD that I want to use in a tablet (Cyanogenmod 11) by formatting it ext4. So I did the usual thing (under Fedora 20): created a single Linux partition with sfdisk, ...
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30 views

How many actual files were you able to store in a CentOS folder?

I found many questions about the total files limitations of the CentOS file-system, but I was curios in actual real-world situation, how many files people were able to store in one single CentOS ...
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43 views

How to modify the starting boundary of an ext4 partition?

There are 4 partitions on the disk. parted /dev/sda --script -- print ... 1 1049KB 50.0GB ... ext4 2 50GB 82GB ... linux-swap 3 82GB 100GB ... ext4 4 100GB 1000GB ... ext4 My goal is to ...
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145 views

Someone please explain how I'm writing to EXT4 from Windows 8.1

I'm dual booting Debian amd-64 Wheezy 7.5 and Windows 8.1 I have 6 drives and I am 100% positive that four of the drives are formatted Ext4 (Formatted in Linux) How on earth is it that when I'm in ...
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185 views

EXT4 external hard drive for use with multiple systems

I recently bought a external hard drive to store some data on. I use Linux but I am not a power user. If I format the drive to EXT4, is it possible for the permissions to ever screw up and I lose ...
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37 views

A file system operation that would incur a seek/rotational cost

I am looking to generate a workload that will do operations on a file system that will make the disk access to have rotational or seeking cost. Env details: partition size: 30 G. File system : ...
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1answer
576 views

Recover Linux ext4 partition formatted(erased) to hfs+

I have a Linux partition with 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 Windows but ...
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968 views

eMMC Standards and File System support

I am looking into Android secure erase functions and realized a few things: Android uses eMMC as its storage media, eMMC standards are set by the JEDEC organization (currently most of the ...
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167 views

Rescue data from ext4 ISO image?

so, my SD card got broken and cannot be read completely (escpacially the directory I want to read from has problems). I was able to create an ISO image of the partition using dd but cannot mount it. ...
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155 views

How does the number of files in the same folder affect I/O performance in an ext4 filesystem

I'm using Kyoto Cabinet (a key-value store) for my project. The specific type of DB I'm using is DirDB which creates a lot of files in a directory to store the key-value pairs. The server I'm running ...
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191 views

Weird behaviour on ext4 dd performance test

I'm testing the performance of ext3/ext4 on a raid1 system (but the same goes for a non raid system). The results from bonnie++ give a distorted image because they circumvent the delayed allocation on ...
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198 views

FreeNAS 8 and ext fs

i'm trying out freenas8 for my personal NAS, i have lots of data that was in an ubuntu server, but somehow i never got the file sharing right. on freenas things just worked. i installed on usb, tried ...
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1answer
330 views

Linux fine tuning for Vertex 3 SSD

I've been reading about optimizations for SSD disks on Linux, there is lots of info out there although very confusing and most feel outdated so I'd be grateful if someone sheds some light on the ...
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1answer
103 views

Quick way to empty a partition

I have a partition, formatted ext4, that I want to empty completely. I will be repeating this write-then-empty process repeatedly, so I want the emptying step to be as quick as possible. One option ...
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1answer
82 views

Dealing with different usernames when mounting removable media in Linux

I have a laptop in which my username is, say, "foo". I have an external drive, formatted with Ext4, for which all files are owned by "foo" (at a filesystem level). Now, I have a desktop in which my ...
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1k views

Mounting external usb harddisk (ext4) in virtual box in windows

I would like to mount my external linux formatted usb harddrive in a virtual machine. The host is windows 7. Unfortunately virtual box doesn't enumerate the external harddrive in the options menu of ...
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566 views

using setfacl to give access to another user without giving access to a group

I have a user that I use for backup, and I use setfacl to give that user access to files. However, setfacl changes the base ACL entry for group and some applications require that the base ACL entry ...
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250 views

Strange file permissions on FAT32 under Ubuntu

On my machine (Lenovo ThinkPad w510, Ubuntu 10.10) I have (at least) two logical partitions: an ext4 partition to which Ubuntu is installed; a FAT32 partition (the bigger one) on which I store all ...
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176 views

Recovering data from two partitions, one NTFS, the other ext4

I have an external HD, and it had three partitions on it. One was a 4GB ext4 filesystem ,and two others 120GB NTFS and 120 GB ext4. I created an image on the 4GB using the Linux utility dd on Fedora ...
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513 views

Does stat/lstat on nonexistent file cause a disk seek?

When searching for a library file from a right folder, my application currently does couple of lstat's for the possible locationslocations. Now I'm wondering whether these lstat's (application is ...
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158 views

How to stop jbd2 to release a device

In an AWS EC2 instance, we have multiple EBS volumes. When I try to detach any of them, the umount command works, but the device can't be detached. # grep -c xvdj /proc/mounts 0 However, lsof ...
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8 views

How can I get Samba to close files immediately?

I've been experiencing a baffling disappearing file issue on my NAS since I first bought it, and only today after extensive testing do I think I have a handle on what exactly is occurring. I fear ...
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102 views

Ext4 allocation pattern with random writes in sparse file

If I create a large (a few GB) sparse file in ext4, and then write randomly throughout the length until all 4k blocks have been "touched", in the absence of other heavy write load, can I expect that ...
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32 views

ext4 superblock checksum?

I'm reading the ext4 superblock, but its s_checksum (offset 0x3FC) is always zero. Also the s_checksum_type (offset 0x175) field is zero as well, however according to ...
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212 views

Contiguous physical allocation of a set of files in linux filesystem (ext4)

I have a set of files that I wish to be allocated contiguously in the filesystem. I will be accessing all these files sequentially in a single read one after the other and I want to optimize reading ...
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68 views

Ubuntu 12.04/xp dual boot testdisk wrote the wrong mbr to my storage disk

Using disk Utility in Ubuntu 12.04, I inadvertently formatted my 1TB ext4 storage disk to NTFS. I was in the process of doing clean installs so I just pulled the drive and set up a usb hdd dock to ...
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209 views

How do I add additional locations to the Windows 7 Recycle Bin Properties?

I have set up a home network with a small file server running Samba. I read on a forum post that by re-mapping a user folder on Windows 7 to a network drive, a reference to that drive will be added ...
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408 views

extundelete does not finish its work

I need to restore a file on sda7 so I remounted ro und startet extundelete manuel@P5KC:~/recovery/RECOVERED_FILES$ sudo extundelete --restore-all /dev/sda7 WARNING: Extended attributes are not ...
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147 views

from XEN to VMWare

I have migrated many xm virtual machine to vmware Using http://www.zoobey.com/index.php/resources/all-articles-list/268-xen-to-vmware , migrations were very smooth. But now I am struck in a xm ...
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249 views

Mounting a remote disk image which I made local via sshfs? Possible?

The core question first: Is sshfs fit to provide low-level reads/writes/seeks as required when a file contains blockdevice-like contents? Why? Well... I am trying to locally mount a filesystem-image, ...
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49 views

How can I identify and read only free-space junk data from EXT4 partition?

I have cloned an EXT4 partition via raw dd command from a Galaxy Nexus phone. How can I identify and read only free-space junk data from the EXT4 partition? I need to recover some WAVE samples(I'm ...
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47 views

Is it possible to recover ext4 journal state before inode corruption?

First of all I'll describe my situation: I decided to make some partitions cleanup, resize, etc (not creating damn backup). Then I wanted to shrink filesystems, so I closed computer and booted some ...
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612 views

Forcing ext4lazyinit to finish its thing?

Is there any way to 'force' ext4lazyinit to finish the thing it does with maximum priority? Something like "I don't care about my system's ressources, just do your job as fast as you can"? I should ...
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161 views

How to run exe files on an ext4 partition using Paragon ExtFS under Windows 7

I've tried Paragon's ExtFS to mount an ext4 partition under Windows 7. I could open documents like PDF files without any problem, and creating and deleting files seems to work well, too (I've only ...
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24 views

Install e2fslibs 1.41

I have to use extundelete for my debian, but it requires e2fslibs 1.41. The command apt-get install e2fslibs-dev installs 1.42 version that is not compatible with it. How to downgrade? I'm usingh ...
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How much data needs to be written to format a drive for ext3 / ext4?

If formatting a hard disk with mkfs.ext3 or mkfs.ext4, how many mb's will be written per mb space formatted?
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318 views

Is ok to limit writes on SSD/EXT4 by setting commit parameter in fstab?

I've installed an SSD on my / (Linux scv 3.8.0-34-generic #49~precise1-Ubuntu SMP Wed Nov 13 18:05:00 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux). If I leave the default settings in /etc/fstab I can see ...
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setting system time at startup from ext4 filesystem

I have a pc with no battery backup and using ubuntu 12.04 with ext4 it will constantly ask me to handle the situation by saying that my superblocks last write is in the future. So I wonder - can I ...
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121 views

Setting up Fedora alongside Windows 8 with special considerations

I've recently found myself much more comfortable using the console and other tools on my Mac than their counterparts with Windows. Specifically, these tools include LaTeX/xindy, emacs and its load ...
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487 views

Cannot mount harddrive from HP ProBook via SATA-USB adapter

I'm trying to mount harddrive from HP ProBook 4525s to another computer for data backup from damaged laptop. There are two ext4 and one swap partition on hdd. I'm using SATA-USB adapter, but after I ...
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216 views

parted killed my ext4 stuff

In parted you're supposed to be able to delete a partition, make a new one, and your data will still be there. It's gone. Nothing, not even testdisk is finding the partition. If I do the same stuff ...
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531 views

Booting an EXT4 image file from GRUB2

My friend needed a fast HDD so I gave her my small 64GB SDD. This SSD had my Linux install on it. I used dd to make an image of the partition (boot, root and home on one partition). This partition is ...
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574 views

My ext4 partition became unreadable

When I boot up my PC (duel boot with Vista, which works fine) and go to ubuntu in the grub menu I get an almost immediate kernel oops. Errors include (from memory) /dev, /proc & /sys doesn't ...