fsck: file system check
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Partitions
To be safe a regular file system check should be regularly performed on every partition of every hard disk that you own.
Before using e2fsck, the partition should be unmounted. This is easy to do with an external drive used for backup, but it requires a special procedure when you want to check the partition where root (/) /usr or /home reside. Thus, we shall consider those scenarios separately.
External device
Internal device (/, /usr, /home)
Interactive
Interactive
# e2fsck -vfFC0 /dev/sdc1 e2fsck 1.41.9 (22-Aug-2009) Pass 1: Checking inodes, blocks, and sizes Error reading block 34308186 (Attempt to read block from filesystem resulted in short read) while getting next inode from scan. Ignore error?
Answering yes will delete the inode, i.e. data will be lost. Answering no will leave the bad block in place and the problem will remain.
Non interactive
The -y option should not be placed after the -C option, as it would be understood as being an argument of the latter. Instead, put it in front.
I.e.
Wrong: e2fsck -vfFC0y /dev/sdc1
Right: e2fsck -yvfFC0 /dev/sdc1
Command output
Document here the various messages or errors output by the fsck commands. The goal is to eventually be able to understand the significance of each message and be informed on what the proper course of action should be.
x% non-continguous
E.g.:
/dev/sda1: 79674/642112 files (2.8% non-contiguous), 2316797/2559744 blocksIs it ok to ignore this?
Free blocks count wrong
# fsck -f /dev/sda2
fsck from util-linux 2.25.2
e2fsck 1.42.12 (29-Aug-2014)
/dev/sda2: recovering journal
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 (191550189, counted=192989110).
Fix? Questions for which we are seeking answers:
- What can cause the above error?
- What to answer to the question "Fix?" What are the implications of answering yes or no?
External resources
http://en.wikipedia.org/wiki/E2fsprogs
http://en.wikipedia.org/wiki/Fsck
http://adminschoice.com/repairing-unix-file-system-fsck
http://lwn.net/Articles/248180/
e2fsck -vfFC0
complete check with maximum output.
Issues related to this page:
| Project | Summary | Status | Priority | Category | Last updated | Assigned to |
|---|---|---|---|---|---|---|
| Linux software | Best use of e2fsck | active | critical | task | 14 years 26 weeks | |
| Linux software | e2fsck: non-desctructive, informative mode only? | active | normal | feature request | 12 years 20 weeks | |
| Linux software | Running e2fsck twice gives the same / differen… | active | normal | support request | 14 years 22 weeks | |
| Linux software | 0 bad blocks ??? | active | normal | support request | 14 years 22 weeks | |
| Linux hardware | fsck: different scenarios for use | active | normal | task | 13 years 2 days | |
| Linux hardware | What is a bad block? | active | normal | task | 12 years 19 weeks |