4
votes
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 ...
0
votes
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
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 ...
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 ...
1
vote
1answer
285 views

Ext4 exhibits unexpected write latency variance vs. ext2

I have a latency sensitive application running on an embedded system, and I'm seeing some discrepancy between writing to a ext4 partition and an ext2 partition on the same physical device. ...
31
votes
6answers
10k views

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?
6
votes
1answer
3k 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 ...
2
votes
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 ...
5
votes
3answers
845 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?
1
vote
1answer
6k views

disabling journal vs data=writeback in ext4 file system

What is the difference between disabling journal on ext4 file system using: tune2fs -O ^has_journal /dev/sda1 and using data=writeback when mounting? I thought ext4 - journal = ext2. means when we ...
6
votes
1answer
618 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
2answers
370 views

Defragging an ext partition?

Why don't ext2/3/4 need to be defragmented? Is there no fragmentation at all?