Tagged Questions

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

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data recovery from form an accidental format on ext4 partition

When I was installing Mint Debian edition unlike the classic edition, the installation automatically formated my home partition when I did not specify to format. So the formatting previously was ext4 ...
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0answers
14 views

Find duplicity files after using PhotoRec

I've partly formatted a disc where my duplicity files was stored. I have used PhotoRec to recover the files but now they're all unsorted and without the correct filename. I have the files separated by ...
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1answer
27 views

How to extract raw ext3 inode data from disk?

On an ext3 (or ext2/4, pick your flavor) filesystem, how would one extract raw byte data that corresponds to a particular inode directly from the hard drive? Is it possible given, say, an inode number ...
3
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1answer
40 views

How to update directory size after file removal?

This is mostly theorethical question without real practical usage. As you may know, filenames are stored in directory inode. That means the more files we have and the longer filenames are the more ...
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1answer
37 views

Unable to delete file “ldlinux.sys” from a partition

I wanted to create live bootable USB of gparted via unetbootin. But by mistake I specified the device of USB as a partition of external HDD rather than the USB drive. I deleted all the files that ...
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0answers
58 views

Grub rescue after corrupted hard-drive (“read-only filesystem”)

I run xubuntu 12.04 alongside a NTFS storage partition and a windows 8 partition. I moved my MySQL data directory off the xubuntu (ext4) partition, onto the NTFS partition, and did an import of a ...
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1answer
57 views

Why the size of an empty directory in Linux is 4KB? [duplicate]

I'm using Ubuntu 14.04 and I made an empty directory on /tmp with the mkdir command: cd /tmp mkdir foo and then I checked it's size using ls: ls -ldh foo and the result shows that the size of ...
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0answers
17 views

Getting partition boundary error when using GPARTED

I am trying to allocate my hard disk with below set of partitions using GPARTED. /dev/sdb1 - 256 MB /dev/sdb2 - 2048 MB With free space preceding as (4 Mb) between partitions. After applying the ...
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0answers
10 views

Many transient files on journaled filesystem?

Writing and deleting many files quickly I'm going to write many temporary files per second, over a sustained period. Each will be deleted after some milliseconds. Say we have an image processing ...
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0answers
103 views

mkfs.ext4: Discarding device blocks: failed - Input/output error

I am trying to format my new SD card, using following command; mkfs.ext4 -O ^has_journal /dev/mmcblk0p2 and I get following error: Discarding device blocks: failed - Input/output error I don't ...
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3answers
70 views

Why does find -inum iterate through the whole filesystem tree?

It surprises me to see find iterate/walk through the complete filesystem when I do a simple find -inum 12345 Without background info it seems to me that there should be much easier ways for to tell ...
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2answers
46 views

How can I mount a filesystem, mapping userids?

I can successfully mount an ext4 partition, the problem is that all the files on the partition are owned by the user with userid 1000. On one machine, my userid is 1000, but on another it's 1010. My ...
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3answers
98 views

How to repair a file system corruption?

Debian on external USB SSD drive. There was some error in dmesg log file: ...[ 3.320718] EXT4-fs (sdb2): INFO: recovery required on readonly filesystem [ 3.320721] EXT4-fs (sdb2): write access ...
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0answers
189 views

Which file system (among XFS, BTRFS and EXT4 only) does provide the best data resilience to disk corruption? [closed]

Question: Given these three filesystems: XFS, BTRFS and EXT4, I'm wishing to know which does provide the best data resilience to data corruption in a setup without RAID. And, of course, why? ...
4
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1answer
192 views

Advantages/disadvantages of increasing “commit” in fstab

I have done many obscure system optimizations in the past, but I got rid of most of them after powertop told me I should set my USB ports to autosuspend, which forced them to an eternal sleep, and ...
1
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1answer
61 views

archlinux check disks on boot

How can I check and mark bad blocks on Linux startup? There are a number of options available and most of them require accessing hardware and running live CD's. But I would like to avoid and perform ...
2
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1answer
705 views

“inode_size (128) * inodes_count (0) too big for a filesystem with 0 blocks” while creating a file system

My partition table looks like this: Device Boot Start End Blocks Id System /dev/sda1 * 2048 32505855 16251904 83 Linux /dev/sda2 32505856 33554431 ...
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166 views

Good Bye lvreduce, hello lvresize?

I've found a couple of times that using lvreduce, (first unmounting, shrinking ext4 with resize2fs, and fsck'ing) ends in: mount: wrong fs type, bad option, bad superblock on ...
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0answers
188 views

CentOS 5.6 expand ext4 partition , have steps but parted shows as ext3

I have a Adaptec 5805 HW RAID card with a 6.3 TB RAID-6 array (partitioned via Parted GPT, all of which is formatted as ext4 on CentOS 5.6). I want to expand this to 7.5GB and from reading these are ...
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1answer
191 views

harddisk not recognized / filesystem too large to mount safely on this system / hdparm shows garbage

I have a 4 TB Verbatim external hard disk with ext4. It can be successfully mounted at my Raspberry Pi. I am trying to plug it at my WD Mybook Live Duo device where I have SSH root access. When I ...
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2answers
342 views

Can overwritten files be recovered?

I am not talking about recovering deleted files, but overwritten files. Namely by the following methods: # move mv new_file old_file # copy cp new_file old_file # edit vi existing_file > D > ...
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0answers
46 views

ext4 data recovery from gparted error

During resizing and moving 2.7TB partition in Gparted, I encountered an error that froze the whole program. (I dont have a screenshot or output from it, as fas as I remember, it was something about ...
2
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1answer
168 views

ext4 filesystems frequently corrupting

We have occasional power outages in our environment which seems to cause data corruption on our Ubuntu machines with ext4 filesystems. To my understanding ext4's default is to use data=ordered ...
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26 views

Could I disable ext4's journaling safely in BBWC?

I knew set "nobarrier" flag is safe in BBWC when using ext4,but since "nobarrier" flag couldn't ensure proper order of journal logging and data flushing,then it seems journaling is useless。So is it ...
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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). ...
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1answer
44 views

Could I set flag “barrier=0” when using SSD?

I'm using ext4 filesystem in SSD,when mounting SSD,could I use flag "barrier=0"? I knew this flag is safe for BBU(battery backup unit),but is it safe for SSD?
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2answers
198 views

Linux: Recover files from .vdi file

Somehow my .vdi (Linux guest OS) file got corrupted. Now I have some files in it (Inside the vdi file) and I want to recover those files. How can I do that?
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2answers
174 views

How to give Windows partions' file execute permission

I have installed Linux Mint 17 and Windows 8, as dual boot. 500GB hard disk has 5 partitions. Two of them are NTFS and the other 3 are ext4 partitions. When I log into Windows, I can not see any ...
2
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0answers
49 views

How can I capture a consistent snapshot of a directory and all its children?

We have an application that periodically backs itself up to a directory on the local file system. Inside this directory are several more files and directories. I want to produce a "snapshot" of all ...
4
votes
1answer
102 views

What is the difference between fsck options -y and -p?

The ext2/3/4 filesystem checker has two options that seem to be very similar, -p and -y. Both seem to perform an automatic repair, but the manpage states that -p can exit when it encounters certain ...
1
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1answer
131 views

ex4 to btrfs conversion: If I accidentally lose power to the system during the conversion, will I lose the data?

I want to convert the 3TB 80% full ext4 block device into btrfs and I want to estimate the risks involved in the process. If I accidentally lose power to the system during the conversion, will I ...
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0answers
21 views

ext4 to btrfs conversion: Can I pause, reboot the system and then resume the conversion? [duplicate]

I want to convert a rather big ext4 volume into btrfs. How long will the process will take?
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1answer
1k views

Is data=journal safer for Ext4 as opposed to data=ordered?

The default journal mode for Ext4 is data=ordered, which, per the documentation, means that "All data are forced directly out to the main file system prior to its metadata being committed to ...
2
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0answers
154 views

Mount from auto to manual and changing dir gives errors

I just installed Ubuntu 14.04 and am trying to mount my internal HD to a different location in the /home/username dir (auto-mount mounts it to /mnt/{uuid} ) But I ran into a problem. In Disks, when ...
6
votes
2answers
1k views

“Converting” a filesystem from ext3 to ext4

I've read on some Q&A on this website that one can "convert" an ext3 filesystem to ext4 without formatting, by issuing tune2fs -O extents,uninit_bg,dir_index /dev/dev-name And then running ...
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3answers
3k views

External hard drive permissions - ext4

I have an external USB 3 disk drive (2TB capacity) that is most likely going to be moved from machine to machine. The disk has a GUID partition table and an ext4 partition. I am unable to write to the ...
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2answers
655 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 ...
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0answers
94 views

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

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
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1answer
77 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. ...
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3answers
283 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 ...
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votes
3answers
208 views

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 ...
2
votes
1answer
232 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: ...
0
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2answers
107 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 ...
1
vote
1answer
198 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 ...
2
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0answers
28 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 ...
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votes
2answers
291 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
88 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
492 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
75 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
86 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 ...