Latest LQ Deal: Latest LQ Deals
Go Back > Forums > Linux Forums > Linux - Newbie
User Name
Linux - Newbie This Linux forum is for members that are new to Linux.
Just starting out and have a question? If it is not in the man pages or the how-to's this is the place!


  Search this Thread
Old 02-25-2008, 01:35 AM   #1
LQ Newbie
Registered: Feb 2008
Posts: 15

Rep: Reputation: 0
Question ext3...doubts

If journaling can be used to recover file system after crashes, why does ext3 still ask for file system check during system boot up?
Old 02-25-2008, 01:48 AM   #2
LQ Guru
Registered: Aug 2004
Location: Sydney
Distribution: Centos 7.7 (?), Centos 8.1
Posts: 17,818

Rep: Reputation: 2558Reputation: 2558Reputation: 2558Reputation: 2558Reputation: 2558Reputation: 2558Reputation: 2558Reputation: 2558Reputation: 2558Reputation: 2558Reputation: 2558
Because it's optional ie if it asks you, it thinks it needs doing, but it's your decision...
Old 02-25-2008, 01:51 PM   #3
LQ Guru
Registered: Oct 2005
Location: $RANDOM
Distribution: slackware64
Posts: 12,928
Blog Entries: 2

Rep: Reputation: 1292Reputation: 1292Reputation: 1292Reputation: 1292Reputation: 1292Reputation: 1292Reputation: 1292Reputation: 1292Reputation: 1292
Well, you see, on boot up, a journaled filesystem will analyze its log file, if the filesystem was not unmounted properly there's probably some lost data, so it looks through the log and tries to recover it, it also looks for possible data corruption. It typically only does this after a crash or when the filesystem is not unmounted properly (i.e. the power goes out before you can shutdown the computer properly).
Old 02-26-2008, 12:12 AM   #4
LQ Newbie
Registered: Feb 2008
Posts: 15

Original Poster
Rep: Reputation: 0
I will give what i found out till now...

e2fsck is used to check a Linux second extended file system (ext2fs). E2fsck also supports ext2 filesystems containing a journal, which are also sometimes known as ext3 filesystems, by first applying the journal to the filesystem before continuing with normal e2fsck processing. After the journal has been applied, a filesystem will normally be marked as clean. Hence, for ext3 filesystems, e2fsck will normally run the journal and exit, unless its superblock indicates that further checking is required.

How much time the check takes? 5 secs or an hour.

If it takes 5 seconds, then it's using the journal. The fsck that's used for ext3 replays the journal to make the filesystem consistent then assumes that everything's OK and continues.

If it takes an hour, then one of the time-between-fscks or mounts-between-fscks counters has expired, and it's doing a full fsck because a journal does not protect against corrupted data.


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
DD Command doubts bharath_neo Linux - Software 9 08-02-2007 07:07 PM
doubts about dd brazilian_user Linux - General 6 09-18-2006 07:58 PM
Several doubts talpa_sai Linux - Newbie 1 09-08-2006 04:06 AM
Ext3 & tune2fs tweaking question for ext3 experts wrc1944 Linux - General 8 12-11-2005 08:45 AM
Doubts in c rajesh_b Programming 2 06-06-2005 10:54 PM > Forums > Linux Forums > Linux - Newbie

All times are GMT -5. The time now is 06:06 AM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Open Source Consulting | Domain Registration