17일차 ext2 ext3 차이, 파일세스템 및 복구

centos2[root /root]# mkfs -t ext3 /dev/sdc2

centos2[root /root]# mkfs -t ext2 /dev/sdc1

포멧 차지점은 ext3dl 전정이가 갑작스러운 다운시 더 안정 적이다.

포멧시 Creating journal (4096 blocks): done 메시지가 더 추가로 나온다.

ext2로 포멧 하고 마운트시  ext3으로 하면 안된다.

ext3로 마운트 한다는 것은 journal 를 사용 한다는 소리다.

반대로 ext3 포멧 하고 ext2 로 마운트는 가능 하다.

centos2[root /dev]# mkdir /mnt/ssdc1

centos2[root /dev]# mount /dev/sdc1 /mnt/ssdc1

centos2[root /dev]# fsck /dev/sdc1

fsck 1.39 (29-May-2006)

e2fsck 1.39 (29-May-2006)

/dev/sdc1 is mounted.

WARNING!!!  Running e2fsck on a mounted filesystem may cause

SEVERE filesystem damage.

Do you really want to continue (y/n)? no   (마운트시 정검 하면 오류 생긴다..마운트 해제 하고 하자`)

check aborted.

centos2[root /dev]#

DD란 디스크를 통체로 복사 한다.

크기가 같아야 복사 가능

centos2[root /dev]#  dd if=/dev/sdc of=/dev/sdd

부팅해줘야 나머지 파티션이 보인다.

하지만 방법이 있다.

fdisk /dev/sdd 로 드어 가서 w 눌러주면 된다.

파티션 복사를 하면 uuid 가 기존하고 똑같다..

그래서 변경 해주어야 한다.

centos2[root /home]# tune2fs -U random /dev/sdd1

tune2fs 1.39 (29-May-2006)

centos2[root /home]#

centos2[root /home]# dumpe2fs /dev/sdc1 | grep - uuid  (명령어로 uuid 화인 하기)

centos2[root /home]# dd if=/dev/zero of=/dev/sdc1 bs=1024 count=10  (dd 명령어를 사용해서 10블록까지 제로로 덮어 쒸운다.

10+0 records in

10+0 records out

10240 bytes (10 kB) copied, 0.0256514 seconds, 399 kB/s

centos2[root /home]# mount /dev/sdc1 /mnt/d3p1

mount: you must specify the filesystem type

centos2[root /home]# 손상되서 마운트가 안된다.

-bash: 손상되서: command not found

centos2[root /home]#

복구방법

centos2[root /home]# fsck /dev/sdc1

fsck 1.39 (29-May-2006)

e2fsck 1.39 (29-May-2006)

Couldn't find ext2 superblock, trying backup blocks...

Resize inode not valid.  Recreate<y>? yes

Superblock last write time is in the future.  Fix<y>? yes

/dev/sdc1 was not cleanly unmounted, check forced.

Pass 1: Checking inodes, blocks, and sizes

Pass 2: Checking directory structure

Pass 3: Checking directory connectivity

Pass 4: Checking reference counts

Pass 5: Checking group summary information

Free blocks count wrong for group #0 (3547, counted=3548).

Fix<y>? yes

Free blocks count wrong (89514, counted=89515).

Fix<y>? yes

/dev/sdc1: ***** FILE SYSTEM WAS MODIFIED *****

/dev/sdc1: 11/24576 files (0.0% non-contiguous), 8773/98288 blocks

centos2[root /home]# fsck /dev/sdc1

fsck 1.39 (29-May-2006)

e2fsck 1.39 (29-May-2006)

/dev/sdc1: clean, 11/24576 files, 8773/98288 blocks

centos2[root /home]# mount /dev/sdc1 /mnt/d3p1

centos2[root /home]#

좀더 심하게 손상

centos2[root /home]# dd if=/dev/zero of=/dev/sdc1 bs=1024 count=1000

centos2[root /etc]# cd /mailhome

centos2[root /mailhome]# ls

1.txt  2.txt  lost+found  mailuser1  mailuser2  mailuser3

centos2[root /mailhome]# cd ..

centos2[root /]# umount /mailhome

centos2[root /]# dd if=/dev/zero of=/dev/sdc1 bs=1024 count=1000

1000+0 records in

1000+0 records out

1024000 bytes (1.0 MB) copied, 0.0526402 seconds, 19.5 MB/s

centos2[root /]# fsck /dev/sdc1

fsck 1.39 (29-May-2006)

e2fsck 1.39 (29-May-2006)

Couldn't find ext2 superblock, trying backup blocks...

Superblock has an invalid ext3 journal (inode 8).

Clear<y>? yes

*** ext3 journal has been deleted - filesystem is now ext2 only ***

Resize inode not valid.  Recreate<y>? yes

/dev/sdc1 was not cleanly unmounted, check forced.

Pass 1: Checking inodes, blocks, and sizes

Root inode is not a directory.  Clear<y>? yes

Pass 2: Checking directory structure

Entry '..' in ??? (4097) has deleted/unused inode 2.  Clear<y>? yes

Entry '..' in ??? (8193) has deleted/unused inode 2.  Clear<y>? yes

Entry '..' in ??? (16385) has deleted/unused inode 2.  Clear<y>? yes

Pass 3: Checking directory connectivity

Root inode not allocated.  Allocate<y>? yes

Unconnected directory inode 4097 (...)

Connect to /lost+found<y>? yes

/lost+found not found.  Create<y>? yes

Unconnected directory inode 8193 (...)

Connect to /lost+found<y>? yes

Unconnected directory inode 16385 (...)

Connect to /lost+found<y>? yes

Pass 4: Checking reference counts

Inode 4097 ref count is 5, should be 4.  Fix<y>? yes

Inode 8193 ref count is 5, should be 4.  Fix<y>? yes

Inode 16385 ref count is 5, should be 4.  Fix<y>? yes

Pass 5: Checking group summary information

Block bitmap differences:  +(1--517)

Fix<y>? yes

Free blocks count wrong for group #0 (3546, counted=7673).

Fix<y>? yes

Free blocks count wrong for group #2 (7934, counted=7922).

Fix<y>? yes

Free blocks count wrong for group #4 (7934, counted=7922).

Fix<y>? yes

Free blocks count wrong for group #8 (7934, counted=7922).

Fix<y>? yes

Free blocks count wrong (89513, counted=93604).

Fix<y>? yes

Inode bitmap differences:  +1 +(3--10)

Fix<y>? yes

Free inodes count wrong for group #0 (2036, counted=2037).

Fix<y>? yes

Directories count wrong for group #0 (3, counted=2).

Fix<y>? yes

Free inodes count wrong for group #2 (2048, counted=2036).

Fix<y>? yes

Directories count wrong for group #2 (0, counted=6).

Fix<y>? yes

Free inodes count wrong for group #4 (2048, counted=2036).

Fix<y>? yes

Directories count wrong for group #4 (0, counted=6).

Fix<y>? yes

Free inodes count wrong for group #8 (2048, counted=2036).

Fix<y>? yes

Directories count wrong for group #8 (0, counted=6).

Fix<y>? yes

Free inodes count wrong (24564, counted=24529).

Fix<y>? yes

/dev/sdc1: ***** FILE SYSTEM WAS MODIFIED *****

/dev/sdc1: 47/24576 files (0.0% non-contiguous), 4684/98288 blocks

centos2[root /]# mount /dev/sdc1 /mailhome

centos2[root /]# df

Filesystem            Size  Used Avail Use% Mounted on

/dev/sda1              14G  3.7G  8.7G  30% /

/dev/sdb1             494M   11M  458M   3% /home

tmpfs                 394M     0  394M   0% /dev/shm

/dev/sdc1              93M  1.6M   87M   2% /mailhome

centos2[root /]# cd /mailhome

centos2[root /mailhome]# ls

lost+found

centos2[root /mailhome]# cd lost+found/      (lost+fount 폴더로 들어 간다.)

centos2[root /mailhome/lost+found]# ls 

#16385  #4097  #8193

centos2[root /mailhome/lost+found]# cd '16385'

-bash: cd: 16385: 그런 파일이나 디렉토리가 없음

centos2[root /mailhome/lost+found]# ls -l   (파일 소유를 확인한다.)

합계 3

drwx------ 4 mailuser3 mailuser3 1024  6월 26 05:33 #16385

drwx------ 4 mailuser1 mailuser1 1024  6월 26 05:33 #4097

drwx------ 4 mailuser2 mailuser2 1024  6월 26 05:33 #8193

centos2[root /mailhome/lost+found]# cd '#16385'

centos2[root /mailhome/lost+found/#16385]# ls

centos2[root /mailhome/lost+found/#16385]# ls -a

.  ..  .bash_logout  .bash_profile  .bashrc  .emacs  .kde  .mozilla  .zshrc

centos2[root /mailhome/lost+found/#16385]# cd ..

centos2[root /mailhome/lost+found]# ls

#16385  #4097  #8193