ext3 (third extended filesystem) is a journaled file system that is commonly used by the Linux kernel.

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How do I know if a partition is ext2, ext3, or ext4?

I just formatted stuff. One disk I format as ext2. The other I want to format as ext4. I want to test how they perform. Now, how do I know the kind of file system in a partition?
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1answer
519 views

How to compact a directory

Every so often, some application runs wild and fills a directory with a huge amount of files. Once we fix the bug and clean up the files, the directory stays big (>50MB) even though there's only 20-30 ...
12
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3answers
3k views

What mount option to use for ext3 file system to minimise data loss or corruption?

I have an embedded setup using an initramfs for the root file system but using a custom ext3 partition mounted on a compact flash IDE drive. Because data integrity in the face of power loss is the ...
11
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7answers
45k 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 ...
9
votes
3answers
858 views

EXT3: If block size is 4K, why does ls -l show file sizes below that?

If you run ls -l on a file that contains one letter, it will list as 2B in size. If your file system is in 4k blocks, I thought it rounded files up to the block size? Is it because ls -l actually ...
9
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1answer
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Difference between block size and cluster size

I've got a question concerning the block size and cluster size. Regarding to what I have read about that I assume the following: The block size is the physical size of a block, mostly 512 bytes. ...
8
votes
5answers
196 views

How to search for files with immutable attribute set?

For config auditing reasons, I want to be able to search my ext3 filesystem for files which have the immutable attribute set (via chattr +i). I can't find any options for find or similar that do ...
8
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2answers
4k views

largefile feature at creating file-system

Is useful to use -T largefile flag at creating a file-system for a partition with big files like video, and audio in flac format? I tested the same partition with that flag and without it, and using ...
8
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2answers
1k views

How to repair an ext3 partition after broken resize operation?

I was using gparted to resize a near-terabyte ext3 partition, adding about 40 GB to the left. After nearly 12 hours of moving data (and with 23 more hours estimated to remain) the system hung. Now ...
7
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2answers
672 views

How to deliberately fragment a file

I am looking for a way to fragment an existing file in order to evaluate the performance of some tools. I found a solution for NTFS file system called MyFragmenter as described in this thread. However ...
6
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1answer
1k views

Significant difference in speed between fsck using ext3 and ext4 on Debian Squeeze

Recently I installed Debian Squeeze, first using ext3 and then again using ext4 on the same machine. The automatic fsck done after a certain number of mounts is much faster using ext4 (about 1 min) ...
6
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1answer
7k views

Mounting an ext3 fs with user privledges

I'm trying to mount an ext3 file system from another linux installation so that the user, not root, will have full access to all the files. (I really do need user to have access to those files, ...
6
votes
1answer
456 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 ...
6
votes
1answer
692 views

How are files laid out in ext2/ext3/ext4?

A few days ago all my metadata on a ext4 format flash card was overwritten. I am now going to speculate on how this happened. This is pure speculation. It happened just after I used a different ...
6
votes
1answer
244 views

md raid1 ext3 and 4k sectors slow with directory operations

I recently moved from a hardware RAID1 enclosure to using two eSATA drives with md. Everything seems to be working fine, except for the fact that directory traversals/listings sometimes crawl (on the ...
5
votes
3answers
1k views

ext2/3/4 reserved blocks percentage purpose

I know that this feature dates back 20 years but I still would like to find out What is the purpose of the reserved blocks in ext2/3/4 filesystems?
5
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1answer
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What is a fragment size in an ext3 filesystem?

This is an output from dumpe2fs: root: ~/# dumpe2fs -h /dev/sdb3 | grep -i 'fragment|block size' dumpe2fs 1.39 (29-May-2006) Block size: 4096 Fragment size: 4096 Fragments ...
5
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3answers
106 views

What makes ext3 determine how frequently to perform file system checks when no options are specified?

I created two partitions on a 1.5 TB drive, the first was 1 TB, the latter was the remaining .5 TB. Both were formatted as ext3. I don't mind the automatic filesystem checks occurring every so often, ...
5
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1answer
822 views

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 ...
5
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2answers
299 views

ext3 Filesystem shows full to most apps, but only 77% full to DF

Var is showing as full to many apps like Nagios, Puppet, and the LVM tools (pvs, vgs, etc) df -h output 6.0G 4.3G 1.4G 77% /var vgs output /var/lock/lvm/V_rootvg:aux: open failed: No space ...
5
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1answer
1k views

How to view bad blocks on mounted ext3 filesystem?

I've ran fsck -c on the (unmounted) partition in question a while ago. The process was unattended and results were not stored anywhere (except badblock inode). Now I'd like to get badblock ...
5
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2answers
1k views

Red Hat cannot boot after clone with dd

I used dd to clone a x4100 server with Linux Red Hat. The hardware is identical for old and new servers. Disks are sda, sdb and sdc(sdc1 and sdc2). But newly restored server gives following errors and ...
5
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2answers
334 views

Testing ext3 filesystem on embedded device [closed]

My set up: An embedded device with flash memory on it. Flash is partitioned into ext3 filesystem partitions. Have busybox on it. My Goal: To uncover errors /bugs/ problems on ext3 filesystems. ...
4
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3answers
1k views

How many bits is the access flags of a file?

How many bits on a linux file system is taken up for the permissions of a file?
4
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2answers
143 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 ...
4
votes
1answer
189 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 ...
4
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1answer
2k views

how much space to reserve on ext3 filesystem to prevent fragmentation issues?

I wondered about some missing space on my ext3 partition and, after some googling, found that debian based ubuntu reserves 5% of the size for root. I also found posts describing how to change that ...
4
votes
1answer
308 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 ...
4
votes
1answer
52 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 ...
4
votes
1answer
2k views

What options are there for tuning Linux file system caching?

What various types of caching are possible in the ext3 file system and how can their values be changed using system calls or other methods? I don't want to use commands or tools.
3
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5answers
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How to check accurately the remaining disk space on a partition?

I have my /home partition formatted as ext3. Occassionally, some program that is part of GNOME is giving notifications about there only being 700mb of space left. Nautilius tells me I have 5.6GB. Disk ...
3
votes
1answer
197 views

How do I choose between ext 3 and 4?

I tried looking at the difference, the main ones seem to be 4 supports more subdirectories in a file, supports larger files, has delayed write which I don't prefer as I don't want data loss. I also ...
3
votes
3answers
219 views

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 ...
3
votes
2answers
2k views

fdisk -l shows ext3 file system as HPFS/NTFS

I have an external HDD which I formatted as NTFS partition in Windows. Now, I formatted this HDD in my linux system using the below command. mkfs.ext3 /dev/sdb1 It was formatted successfully. ...
3
votes
2answers
3k views

Making an ext3 filesystem image without mkfs.ext3

On ubuntu I'm using the following to create a ext3 filesystem image system.img. dd if=/dev/zero of=./system.img bs=1000000 count=200 mkfs.ext3 ./system.img I'm attempting to do the same on android ...
3
votes
2answers
954 views

Recover formatted ext3 partition

Suppose you have an ext3 partition which was unfortunately formated as ext4 partition (and where now are some but not a lot new files on it). Is there any way to recover (some) files from the old ext3 ...
3
votes
3answers
174 views

Is maximum individual file size in ext3 imposed on mysql tables?

I am reading about the file systems in Linux from here. This particular sentence kind of confuses me. For ext3, Maximum individual file size can be from 16 GB to 2 TB. Overall ext3 file ...
3
votes
1answer
97 views

md5sum change after mount?

I have a ext3 filesystem on a .img file. After mounting and unmounting it, I noticed that the md5sum is changed, even if no file inside was changed! md5sum myfilesystem.img XXXX myfilesystem.img ...
3
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2answers
912 views

Besides the journal, what are the differences between ext2 and ext3?

I just saw an answer question about filesystems for embedded hardware on another Stack Exchange site. The question was "What file system format should I use on flash memory?" and the answer suggested ...
3
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2answers
1k views

What does file version mean: lsattr -v

lsattr -v gives me the "version number" of given file(s). What does this mean? On Redhat 7.3, I could've sworn all the version numbers were 1 except those I changed with chattr -v. On Fedora 11, ...
3
votes
2answers
619 views

Location of inodes (ext)?

Say I want to observe how the flow from file name to cluster on hard disc goes. I get the inode number of I file (which is mapped in a directory data): 1863 autorun.inf So, now i know that i have ...
3
votes
1answer
780 views

Where can I see the last mount time?

E.g: I need to know when was the last time a pendrive was mounted. Where could I see that? The pendrive has e.g.: FAT32, EXT3 filesystem.
3
votes
1answer
132 views

Is there a problem using resize2fs too often?

I have a partition which contains MySQL data which is constantly growing. My LVM PV has precious little free space remaining and therefore I find I'm frequently adding additional space to my /var ...
3
votes
3answers
281 views

More free blocks than reserved, but still I get “no space on device”

As you see in this dumpe2fs -h output (snipped the end, left the head in case something is important), I have more (about 86000 more, in fact) 'Free blocks' than are reserved, but I get a "no space on ...
3
votes
1answer
60 views

Automatically set file attributes in a given directory

Let's say I want to set one or more attributes (in the chattr sense) on every file created in a given directory. Is there a way to achieve this automatically, like umask does for file permissions ? ...
3
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2answers
314 views

Allocate file at a specific offset in ext3/4

For benchmark and testing purposes I need to be able to allocate a file at a specific offset from the start of the partition. When I create a new file normally, its blocks are placed wherever the file ...
3
votes
1answer
189 views

EXT3 file system pre digest material

I am looking for understanding EXT3 filesystem source code. I think I need a little pre-digestion to fully understand the code. Can anyone please suggest some material(blog etc.) where I can get some ...
3
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0answers
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linux io stack analysis

I'm trying to understand the Linux IO stack by analyzing blktrace trace. Below is the trace i captured by executing simple fio sequential write with no Direct IO (5 x 8k request size). 8,16 1 ...
3
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0answers
282 views

Confusion with how to restore corrupt ext3 files if power outage occurs during a file write

I am running a small embedded system. Because the system will never be gracefully shutdown and will just have the power cable unplugged, I am running an initramfs but mounting an ext3 partition on a ...
3
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1answer
155 views

What would happen if we mounted a file system that e2fsck is already running on?

It is generally a bad idea to e2fsck a file system while the file system is mounted (the man page mentions one specific situation where it is safe: -n given, and -c, -l or -L not given, and even then ...