The ext4 or fourth extended filesystem is a journaling file system for linux/*nix developed as the successor to ext3.

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Why does deleting a big file take longer?

My understanding is that running rm on a file simply unlinks it, marking the space as free in the filesystem. It should then follow that deleting one file always takes roughly the same amount of time ...
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Storing and backing up 10 million files on Linux

I run a website where about 10 million files (book covers) are stored in 3 levels of subdirectories, ranging [0-f]: 0/0/0/ 0/0/1/ ... f/f/f/ This leads to around 2400 files per directory, which is ...
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Which filesystem for large LVM of disks (8 TB)?

I have a Linux server with many 2 TB disks, all currently in a LVM resulting in about 10 TB of space. I use all this space on an ext4 partition, and currently have about 8,8 TB of data. Problem is, I ...
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What is the maximum number of files a file system can contain?

Given the current structure of a directory entry on a ext4 file system on Ubuntu, what is the maximum number of files a file system can contain? What is the general method of calculating the maximum ...
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“safe” ext4 configuration for systems running unattended

I have a system running linux that must run unattended for long periods of time. The system uses industrial CF card for storage. Most of the time there are no writes to flash, although every now and ...
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Production-ready, highly reliable filesystems on Linux: ext4 ext3 XFS or JFS (or ZFS)?

The last real question I've seen on this topic is from about two years ago (is ext4 ready for production usage). In the intervening time, how has ext4 improved? XFS, JFS, and ext3 are the standby ...
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Is the F.U.D. about ext4 justified? Or would it be safe to use in some production systems?

I am wondering if ext4 is safe to use on my servers. But I've heard so much FUD about it that I am concerned. Our system could lose some data, and it would not be too big a deal. Even a full days ...
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Ensuring a repeatable directory ordering in linux

I run a hosted continuous integration company, and we run our customers' code on Linux. Each time we run the code, we run it in a separate virtual machine. A frequent problem that arises is that a ...
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Is btrfs production ready?

I've seen a lot of information on btrfs lately. I have been considering ext4 for my next filesystem, but am tempted by btrfs instead. How widely used is btrfs? What are the pro's and con's?
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ext4 listing of files very slow in one specific directory that contained lots of files before

Background I had a small logrotate misshap... Logrotate would rotate the archived logs by misstake causing a quadratic growth of files in my /var/log/. And by the time I caught wind that something ...
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What are the differences between ext3, ext4 , ReiserFS?

And why should I pick one instead of the other?
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max files per directory in ext4

I manage an application that contains a filestore in which all the files are stored with the filenames equal to their md5 sums. All files are stored in one directory. Currently there are thousands, ...
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SSD TRIM (discard) problems with ext4 on Crucial C300 SSDs with CentOS 5.5

Playing around with using a modern kernel (2.6.37 currently) on an older OS (CentOS 5.5) so we can get TRIM (discard) working on our SSDs (Crucial C300s). The most recent hdparm (9.37) concurs that ...
11
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How can I recover an ext4 filesystem corrupted after a fsck?

I have an ext4 filesystem on luks over software raid5. The filesystem was operating "just fine" for several years when I was beginning to run out of space. I had a 9T volume on 6x2T drives. I began ...
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is there such a thing as a 'quick' format for ext4?

in Windows it's very fast to format with NTFS. I have a low powered Linux machine, with little RAM. formatting a 2TB volume to ext4 takes a long long time is there anything I can do to speed up ...
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How does the number of subdirectories impact drive read / write performance on Linux?

I've got an EXT3 formatted drive on a Linux CentOS server. This is a web app data drive and contains a directory for every user account ( there are 25,000 users ). Each folder contains files that ...
8
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EXT4 performance has become really bad on system with lots of small files

I have a small embedded device that has only 128MB of RAM attached to this device is a 2TB USB2 hard disk I've been very happy with the performance of the device up until recently when either the ...
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Causes of sudden massive filesystem damage? (“root inode is not a directory”) [closed]

I have a laptop running Maverick (very happily until yesterday), with a Patriot Torx SSD; LUKS encryption of the whole partition; one lvm physical volume on top of that; then home and root in ext4 ...
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Linux: Why change inode size?

Tune2fs allows to change inode size from default 128 bytes to almost anything, but it should be power of two. What are the reasons for changing default inode size? Here it's written that this can be ...
8
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How do you create large, growable, shared filesystems on Linux at AWS?

What are acceptable/reasonable/best ways to provide large, growable, shared storage at AWS, exposed as a single filesystem? We're currently making 1TB EBS volumes ~biweekly and NFS exporting with ...
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Ext4 partition bigger than 2TB?

Is there a way to make partition bigger than 2 TB on ext4 file system ?? Im trying to do that on debian but get message Partition size can not exceed 2TB ...
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Which “features” of ext4 existing ext4 partition uses?

When I create ext4 filesystem, there are many "features", which I can enable and disable - like has_journal, extent, huge_file and so on. Is there any way to know, which options were used while ...
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How do I find a file on Linux in an ext4 filesystem that's being written to frequently?

I've got a Ubuntu system which is writing a block to disk every 1-2 seconds. Some kind of log accruing an error. How do I find which file it is? I've been poring over lsof output and tailing ...
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ext4 file-system max inode limit - can anyone please explain?

Recently we had a problem where one of the ext4 file-systems seemed unable to handle very large number of files, more than 6mln in this case, in spite of having enough space. Is it 6mln the max ...
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Best way to 'harden' embedded ext4 file server against unexpected loss of power?

First, a little background: my company makes an audio streaming device that is a headless, rack-mounted Linux box with a Solid State e-SATA drive attached. The drive is formatted with ext4. The ...
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How to find biggest (in entries, not size) ext4 directory?

Ubuntu 10.04.3 LTS x86_64, I am seeing the following in /var/log/messages: EXT4-fs warning (device sda3): ext4_dx_add_entry: Directory index full! Relevant info from dumpe2fs: Filesystem features: ...
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Whats “Birth” field in stat command output

I'm using Fedora-16 with ext4.Suddenly with stat command I can see something called "Birth". # stat history_file1.txt File: `history_file1.txt' Size: 8944 Blocks: 24 IO ...
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Best options to create and mount an ext4 volume containing > 10M files in one directory

What are the appropriate options to mkfs and mount for an ext4 filesystem with a folder containing >10 million files for read access? What I have so far: umount /media/dirsizetest mkfs.ext4 -L ...
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Convert a software raid volume from ext3 to ext4 (or ext2)?

I have an mdadm created software raid volume in my ubuntu linux 11 machine. It is NOT the boot drive. It is a software raid 5 configuration made from 3 large sata drives. When I created it ...
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How to recover data from a messed up drive (LVM written on top of Ext4)?

The previous administrator of a server that is now under my supervision made a mistake. He accidentally created a LVM volume (no more than pvcreate, I think, though not sure) on a disk that actually ...
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How to get checksum data integrity on ext4?

On file systems like btrfs you can preform a scrub, which will go though all the data to see if the data still matches the file system checksum. I would like to check the data on ext4 if it is ...
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PERC 6/i | ext4 | raid5 | 4 disks - improve write performance

I am running several fileservers using this controller, filesystem and disk setup. All of them are suffering from poor write performance, once the 256MB BBU Write Cache is full i get really high ...
5
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5.5GB written daily to 1.2GB root volume - 4 times previous levels

Problem: I recently revamped one of my servers, it was tested prior to use, and functions well, however, a few days ago, I noticed approximately 4 times the usual amount of writes to the root volume. ...
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Ext4 superblock corrupted after successful(?) mdadm grow and resize2fs

Some system details AMD Phenom II X6 1090T, 16GB DDR3 1600 running 11.04 natty, 2.6.38-8-server Raid in question consists of 5 SATA drives; 4 Samsung, 1 Western Digital; 500 GB each Drives are ...
5
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upgrading ext3 fs on ubuntu 8.04

so we are stuck with this closed source system that keeps on adding folders to one directory, and it's going to hit the 32k limit soon because it's ext3. and that folder is expected to have +100k ...
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e2fsck extremely slow, although enough memory exists

I've got this external USB-Disk: kaefert@blechmobil:~$ lsusb -s 2:3 Bus 002 Device 003: ID 0bc2:3320 Seagate RSS LLC As can be seen in this dmesg output, there is some problem that prevents that ...
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Disk (EXT4) suddenly empty without any sign of why

I have a Ubuntu 10.04 server with several disks in it. The disks are setup with a union filesystem, which presents them all as one logical /home. A few days ago, one of the disks appears to have ...
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exportfs: Warning: /home/user/share does not support NFS export

'exportfs -r' returns me this error when I'm trying to export /home/user/share (ext4): exportfs: Warning: /home/user/share does not support NFS export. /etc/exports: /home/user/share ...
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fsck.ext4: How to force to check the whole file system?

It seems fsck.ext4 quit very soon, I guess it only checks the journal logs, and do nothing if the journal is clean. Is it? How to force it to check the whole file system? I've tried the -f option, but ...
4
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rsync copies unmodified files between different file systems

I try to synchronize files between two machines using rsync, but it seems to copy all the files regardless file modification time. Two consecutive call of the command produces the same results, so it ...
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On linux, what does it mean when a directory has size 0 instead of 4096?

Here's a strange thing I haven't seen before -- a directory whose size is reported by ls as 0 instead of 4096, and I can't create any files within it. # ls -ld lib home drwxr-xr-x. 2 root root 0 ...
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df reports wrong free space for an Ext4 partition

My system is CentOS 6 x86_64 with root partition formatted as ext4. df reports around 3Gb as used space: Filesystem 1K-blocks Used Available Use% Mounted on /dev/md1 ...
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Mount a ext4 partition on Mac OS X

Is it possible to mount a Linux ext4 partition on Mac OS X? Please describe the procedure - risk free - thanks. Edit Aug 2012 The best solution I found was to use a 2nd machine with Linux, mount ...
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Can't resize2fs - combination of flex_bg and !resize_inode

I recently set up my first software raid with mdadm and after adding more disks to the raid I am unable to resize the filesystem to the full size of the raid. I created a single (~16TB) filesystem on ...
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Any way to recover ext4 filesystems from a deleted LVM logical volume?

The other day I had a proper brain fart moment while expanding a disk on a Linux guest under Vmware. I stretched the Vmware disk file to the desired size and then I did what I usually do on Linux ...
4
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Does increasing the journal size improve performance for ext4 filesystems?

There is an article on linux-mag which says that increasing the size of the journal on ext4 filesystems actually improves filesystem performance for very large partitions. I'm wondering if anyone ...
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Failed MDADM Array With Ext.4 Partition - “e2fsck: unable to set superblock flags on /dev/md0”

Had a power failure and now my mdadm array is having problems. sudo mdadm -D /dev/md0 [hodge@hodge-fs ~]$ sudo mdadm -D /dev/md0 /dev/md0: Version : 0.90 Creation Time : Sun ...
4
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Ext4 cache options on a virtual machine

I'm trying to speed up a standup of virtual machines used for development / automated test environments and wanted to verify some assumptions about disk writes caching. I'm using ext4 for the root ...
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Journaled filesystems and power failure

I heard that even a journaled filesystems such as EXT3/EXT4 might corrupted during power failure, e.g. from wikipedia [1]: In the event of a system crash or power failure, such file systems are ...
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ext4 fs breaking after power outages

I am experiencing quite a typical but strange problem: the hdd is going bust after power cuts on my server. I can feel it huge work done by fsck on startup after the crash, and then my subversion ...