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

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Sync writes very slow. Ubuntu 10.10, 32 bits, ext4

I am running ActiveMQ on my Macbook Pro that runs Ubuntu 10.10, 32 bits with an ext4 partition. Linux iker-laptop 2.6.35-23-generic-pae #40-Ubuntu SMP Wed Nov 17 22:32:51 UTC 2010 i686 GNU/Linux If ...
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0answers
21 views

Large ext4 partition ridiculously slow when writing

We have four identical Linux servers with a large (5T) hard disk partition. We have Scientific Linux with this kernel: Linux s3.law.di.unimi.it 2.6.32-358.18.1.el6.x86_64 #1 SMP Tue Aug 27 14:23:09 ...
3
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0answers
17 views

Optimal rootflags for rootfs for ext4 file system running on USB thumdrive [on hold]

I have made myself a bootable USB Debian 7 thumbdrive, using debootstrap. It boots nicely - but occasionally freezes for a bit. I can see the load average is much higher than the running tasks should ...
3
votes
1answer
37 views

Where does ext4 store directory sizes?

Where does ext4 store directory sizes? Are they stored in the directory inode? For example, when I run du -h, it returns directories' size instantly, so I don't believe it calculates it at that time. ...
1
vote
3answers
59 views

How much storage overhead comes along with cryptsetup and ext4?

I want to encrypt the content of a directory in a container with an ext4 filesystem using cryptsetup. The size of the container should be as small as possible and as big as necessary, because I only ...
3
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3answers
686 views

Which file system to choose for small sized files?

I have a partition and it has ~100 GB of audio files. Most of them are mp3 or ogg, each has size of ~15 MB. I update it on a weekly basis. Right now, the partition is formatted as ext4. I have read ...
0
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2answers
22 views

I accidentally formatted the wrong volume - is it possible to restore the previous Ext4 filesystem?

I know that a similar question has already been asked. This morning I accidentally formatted the wrong volume, containing mostly video files (about 30GB each). I am currently trying to restore the ...
2
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1answer
41 views

Why does fstrim trim all of the free space on my mdraid mirror after a reboot? [duplicate]

I have a server with 2 SSDs: Model Family: Intel 520 Series SSDs Device Model: INTEL SSDSC2BW240A3F Firmware Version: 400i User Capacity: 240,057,409,536 bytes [240 GB] Sector Size: ...
1
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1answer
41 views

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 ...
3
votes
2answers
411 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 ...
10
votes
7answers
34k views

Tell fs to free space from deleted files NOW

Is there a way to tell the kernel to give back the free disk space now? Like a write to something in /proc/ ? Using Ubuntu 11.10 with ext4. This is probably an old and very repeated theme. After ...
4
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2answers
53 views

Reliable way to detect ext2 or ext3 or ext4?

I need to detect a filesystem type from a C/C++ program using the filesystem superblock. However, I don't see much differences between superblocks for ext2 and ext4. The s_rev_level field is the same ...
3
votes
1answer
58 views

Something like VMware “Changed Block Tracking” (CBT) in linux

I'm wondering if is there any possibility to track changed blocks in linux with an ext3/ext4 filesystem (or a specific one supporting it). I mean a feture like the Changed Block Tracking (CBT) ...
2
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0answers
12 views

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 ...
3
votes
1answer
23 views

ext4 inode size, shown by dumpe2fs

Manpage about mke2fs says "mke2fs creates 256-byte inodes by default". I've formatted my small (320MB) test partition with command: sudo mkfs -t ext4 /dev/sdc1 The defaults for the mke2fs are ...
4
votes
1answer
182 views

chmod does not change permissions of certain directories

System file: ext4 I changed the owner of files to apache: with the command: chown -R apache: wp.localhost Then, I could not change the permissions of directories in wp.localhost nor the ...
1
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1answer
44 views

Why is it impossible to change the inode count of an ext filesystem?

I know that it isn't possible to change the inode count of an ext filesystem after its creation, but I haven't been able to find any explanation on why it isn't. Can anyone enlighten me?
3
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1answer
51 views

ext4, why 70k file takes 88 blocks

[root@xx]# cat -n create_extents.sh 1 #!/bin/bash 2 3 if [ $# -ne 2 ] 4 then 5 echo "$0 [filename] [size in kb]" 6 exit 1 7 fi 8 9 ...
0
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1answer
27 views

Are there any tools to recover files from a previously formatted WinNT drive?

I scratched the previous Windows NT filesystem, now I'm running Ubuntu. I've created the whole disk as EXT4. Are there any tools to locate and save some previous Windows files from the original ...
4
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2answers
3k views

What's the meaning of output of lsattr

I'm wondering what the output of lsattr means.It prints so oddly as follows,when I have tried: lsattr /usr. $ lsattr /usr -----------------e- /usr/local -----------------e- /usr/src ...
2
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0answers
55 views

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. ...
3
votes
2answers
367 views

Fix EXT4-fs bad geometry (block count exceeds size of device)

I have a micro SD card which has a FAT32 partition and an EXT4 partition. The EXT4 partition will no longer mount. dmesg shows the following error: EXT4-fs (sdb2): bad geometry: block count ...
2
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4answers
274 views

How do I find the offset of an ext4 filesystem?

I have a failing hard drive that is unable to write or read the first sectors of the disk. It just gives I/O errors and that is all there is. There are other areas on the disk that seem (mostly) fine. ...
2
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2answers
2k views

Arch Linux fails to boot from a USB key (cannot mount selected partition)

I tried to install Arch Linux to an USB key. Things are kind of wobbly (it assumes the system has exactly one drive inside, for example) but everything installed just fine. Until I rebooted. ...
1
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1answer
18 views

recovering /home folder from faulty drive

I was going to try ddrescue to recover data from a faulty (beeping) laptop drive and a primary ext4 partition. Reducing the number of reads from the disk should reduce the recovery time and increase ...
1
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4answers
33 views

targeting a specific block with e2fsck to shorten wait

Recently had a LVM'd CentOS 6.5 install get accidentally cold-shutdown. On bootup, it says that the home partition need fscking: /dev/mapper/vg_myserver-lv_home: Block bitmap for group 3072 is not ...
0
votes
1answer
41 views

Recovering truncated file

I'm in a peculiar situation. While editing a Perl program I accidentally truncated the file to zero length (using an Emacs lisp code I was developing). I need to recover that program... How do I that ...
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0answers
39 views

Optimization for an SSD?

I am running Fedora 20 on a Laptop ( Lenovo Ideapad Yoga 2 Pro ) with an SSD. My filesystem is LVM with ext4 as the format option. I am now running Fedora as the only OS on the system with Legacy BIOS ...
0
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1answer
16 views

mke2fs difference between -i and -I options

sudo mke2fs Usage: mke2fs [-c|-l filename] [-b block-size] [-C cluster-size] [-i bytes-per-inode] [-I inode-size] [-J journal-options] [-G flex-group-size] [-N number-of-inodes] [-m ...
2
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0answers
40 views

Do ext(4?) filesystems intrinsically store newer data in a fashion that is more prone to corruption?

I recently had a corrupted ext4 filesystem throwing these errors: kubuntu@kubuntu:~$ sudo mount -t ext4 /dev/sdc2 c1 mount: wrong fs type, bad option, bad superblock on /dev/sdc2, missing codepage ...
3
votes
1answer
179 views

Short read while trying to open partition

On my personal home computer running Kubuntu Linux 13.04 I'm having trouble mounting a partition that is very dear to me. My backup policy is to perform a backup about monthly, so I do have a backup ...
0
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0answers
50 views

e2fsck -y /dev/sda changed my 6TB disk into 1.8TB

After problems with mount I run e2fsck -y -b BLOCK /dev/sda and it was running for 3 days on 6TB raid 0, when it completed this was the output: /dev/sda: ***** FILE SYSTEM WAS MODIFIED ***** ...
2
votes
1answer
67 views

Same file with different content on every read [closed]

I have a problem with a filesystem here on a storage machine. We noticed, that many of the data that comes out of the systems seams to be corrupt, but only with minor problems like CRC errors with ...
3
votes
3answers
73 views

Ext4 - How to enable extra sanity, checksums, validations, tests of any kind?

I'm running Ext4 on a harddrive, and to be perfectly honest, I don't really trust the drive because it's old and has a few badblocks. I have nonessential data on the drive, so if it died tomorrow, ...
1
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1answer
113 views

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 ...
3
votes
1answer
56 views

File containing ext filesystem

Let's suppose I create a file, map it to /dev/loop0, and create a LUKS partition inside dd if=/dev/zero of=myfile bs=1M count=1000 losetup /dev/loop0 myfile cryptsetup -c aes-cbc-essiv:sha256 -s 256 ...
3
votes
2answers
958 views

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 ...
2
votes
2answers
232 views

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 ...
2
votes
1answer
67 views

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 ...
3
votes
1answer
98 views

“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 ...
0
votes
1answer
47 views

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... ...
4
votes
1answer
108 views

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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1answer
137 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.
2
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1answer
660 views

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 ...
3
votes
2answers
2k views

Finding the offset for ext4 partition

I've created an image of my hd with dd, but grub was installed on it, and I'm trying to figure out how to mount the image file, but mount doesn't recognise it as an ext4 partition because of the grub ...
2
votes
0answers
69 views

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 ...
18
votes
4answers
26k views

Recovering ext4 superblocks

Recently, my external hard drive enclosure failed (the hard drive itself powers up in another enclosure). However, as a result, it appears its EXT4 file system is corrupt. The drive has a single ...
6
votes
3answers
6k views

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 ...
0
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0answers
57 views

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 ...
2
votes
2answers
470 views

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 ...