Fsck .

• fsck

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IBM AIX - POWER/PowerPC-based systems

1 It was the first Operating System to introduce the idea of a journaling file system, JFS, which allowed for fast boot times by avoiding the need to ensure the consistency of the file

systems on disks (see fsck) on every reboot


Git (software) - Characteristics

1 To check integrity, run the git fsck command.


inode - Practical considerations

1 Many computer programs used by system administrators in UNIX Operating Systems often designate files with inode numbers. Examples include popular disk integrity

checking utilities such as the fsck or pfiles. Thus, the need naturally arises to translate inode numbers to file pathnames and vice versa. This can be accomplished using the

file finding utility find with the -inum option, or the ls command with the proper option (-i

on POSIX compliant platforms).


Btrfs - Checking and recovery

1 Unix systems traditionally rely on "fsck" programs to check and repair

filesystems. The btrfsck program is now available but, as of May 2012, it is

described by the authors as "relatively new code" which has "not seen

widespread testing on a large range of real-life breakage", and that "may cause

additional damage in the process of repair".


Hard disk drive - Integrity and failure

1 For logical damage to file systems, a variety of tools, including fsck on UNIX-like systems and CHKDSK on

Windows, can be used for data recovery


Unix - Components

1 System utilities – administrative tools such as mkfs, fsck, and many

others.


ext3 - Advantages

1 The ext2 and ext3 file systems share the same standard set of utilities, e2fsprogs, which includes an fsck

tool


ext3 - Functionality

1 ext3, like most current Linux filesystems, cannot be fsck-ed while

the filesystem is mounted for writing. Attempting to check a file system

that is already mounted may detect bogus errors where changed data has not reached the disk yet, and

corrupt the file system in an attempt to "fix" these errors.


IBM AIX (operating system) - POWER/PowerPC-based systems

1 It was the first Operating System to introduce the idea of a journaling file system, IBM Journaled File System 2

(JFS2)|JFS, which allowed for fast boot times by avoiding the need to ensure

the consistency of the file systems on disks (see fsck) on every reboot


Kyoto Cabinet - Practical functionality

1 If inconsistency of the database is detected when opening the

database, all regions are scanned as with fsck and the database is

reconstructed with surviving records implicitly.


Lustre (file system) - History

1 This contract covered the completion of features, including improved Single Server Metadata Performance scaling, which allows Lustre to

better take advantage of many-core metadata server; online Lustre distributed filesystem

checking (LFSCK), which allows verification of the distributed filesystem state between data and

metadata servers while the filesystem is mounted and in use; and Distributed Namespace (DNE),

formerly Clustered Metadata (CMD), which allows the Lustre metadata to be distributed across

multiple servers


Lustre (file system) - Release history

1 The MDS LFSCK feature can verify and repair the Object Index (OI) file

while the file system is in use, after a file-level backup/restore or corruption


Lustre (file system) - Release history

1 The LFSCK feature allows scanning and verifying the internal consistency of the MDT FID and LinkEA attributes


ZFS - Resilvering and scrub

1 ZFS has no fsck repair tool equivalent, common on Unix filesystems, which does

file system validation and file system repair.No fsck utility equivalent exists for ZFS. This utility has traditionally served two purposes, those of file system repair and file system validation. Instead, ZFS

has a repair tool called scrub which examines and repairs silent corruption

and other problems. Some differences are:



1 * fsck must be run on an offline filesystem, which means the

filesystem must be unmounted and is not usable while being repaired.



1 * fsck usually only checks metadata (such as the journal log) but never checks the data itself. This means, after an fsck, the data might still be

corrupt.



1 * scrub checks everything, including metadata and the data. The effect can be observed by comparing fsck to scrub times — sometimes a fsck on a large RAID completes in a few

minutes, which means only the metadata was checked. Traversing all metadata and data on a large RAID takes many hours, which is exactly

what scrub does.https://store.theartofservice.com/itil-2011-foundation-complete-certification-kit-fourth-edition-study-guide-ebook-and-online-course.html

Unix File System - Implementations

1 To overcome the remaining issues after a failure, a background fsck utility was

introduced.


Unix File System - Implementations

1 FreeBSD 9.0 adds support for lightweight journaling on top of

softupdates(SU+J), which greatly reduces the need for background fsck, and uses NFS-style ACLs by

default.


Microsoft ScanDisk

1 On Unix-like systems there are

tools like fsck_msdosfs to do

the same task.https://store.theartofservice.com/itil-2011-foundation-complete-certification-kit-fourth-edition-study-guide-ebook-and-online-course.html

Fsck

1 The system utility 'fsck' (for 'f'ile 's'ystem 'c'hec'k') is a tool for

checking the consistency of a file system in Unix and Unix-like

operating systems, such as Linux and Mac OS X.


Fsck - Use

1 Generally, fsck is run automatically at boot time. There are two common triggers for automatically executing fsck. Either the

operating system detects that a file system is in an inconsistent state (likely due to a non-graceful shutdown such as a Crash

(computing)|crash or power loss), or after a certain number of times that the file system

is mounted (to prevent small, undetected inconsistencies from becoming

exacerbated).https://store.theartofservice.com/itil-2011-foundation-complete-certification-kit-fourth-edition-study-guide-ebook-and-online-course.html

Fsck - Use

1 The fsck command works directly on data-structures that are internal, and intrinsically specific to a file system implementation. A

matching fsck command that is tailored specifically to the design of the file system is

often provided by the authors of a file system. The exact behaviors of various fsck

implementations vary, but they typically follow a common order of internal operations

and provide a common command-line interface to the user.


Fsck - Use

1 Most fsck utilities provide options for either interactively repairing

damaged file systems (the user must decide how to fix specific problems),

automatically deciding how to fix specific problems (so the user does not have to answer any questions), or reviewing the problems that need

to be resolved on a file system without actually fixing them


Fsck - Use

1 A journaling file system is designed such that tools such as fsck do not

need to be run after unclean shutdown (i.e


Fsck - Use

1 While fsck usually only checks metadata, such as the journal log, but never checks the data itself,

scrub checks everything, including metadata and the data


Fsck - Use as profanity

1 Because of the severity of fsck not being able to resolve this error, the terms fsck and fscked have come

into use among Unix system administrators as a minced oath.



1 A report from a question and answer session at USENIX 1998 claims that fsck originally had a different name.



1 :Dennis Ritchie: Well, the second letter was

differenthttps://groups.google.com/forum/#!msg/alt.sysadmin.recovery/tsGbbkvHo2c/6T-Pj9d3A6wJhttp://www.c2.com/cgi/wiki?MindFsck



1 Another online use of the term, not really profanity but a curt way of dismissing someone, was Go fsck

yourself, meaning to go and correct your issue (attitude, ignorance of the subject matter, etc.) before posting

again. This takes the fsck process as a metaphor, since running fsck involves rebooting and fixing

fundamental errors on the hard drive before continuing work on the

computer.


Expect

1 It is used to automate control of interactive application software|applications such as telnet, ftp,

Passwd (command)|passwd, fsck, rlogin, tip (unix utility)|tip, Secure

Shell|ssh, and others


Fuck - Common alternatives

1 Huff Jr., Re: Mandrake 8.2 Musings, alt.os.linux.mandrake,

[http://groups.google.com/group/alt.os.linux.mandrake/msg/3641a310fcc6ed93?dmode=source

Google Groups] At some point in your Linux career you should ask yourself: 'If there are

3.4million successful, happy Mandrake users...what the 'fsck' is wrong with me?' In

Battlestar Galactica the bowdlerized form 'Frak (expletive)|Frack' (spelt 'Frak (expletive)|Frak' in

the Battlestar Galactica (reimagining)|reimagined 2003 version) was used as a substitute for fuck


List of DOS commands - CHKDSK

1 Equivalent to the Unix command fsck


AdvFS

1 The original team had enough confidence in its log based recovery

to release it without an fsck style recovery utility on the assumption that the file system journal would always be allocated on mirrored

drives.


EncFS - Advantages

1 * Corruption of data is more isolated. Data corruption of filedata is local to a single file and data corruption of

the filesystem can be corrected with a reliable filesystem repair utility like fsck. In some whole-disk encryption

systems, one or both of these attributes are not present.


F2FS - Implemented

1 * Offline Fsck|filesystem check (Check and fix

inconsistency[https://lkml.org/lkml/2014/9/20/104 f2fs-tools: release 1.4.0]

by Jaegeuk Kim)


DRBD - Mode of operation

1 This transition may require a subsequent verification of the

integrity of the file system stacked on top of DRBD, by way of a fsck|filesystem check or a journaling

filesystem|journal replay


HFS Plus - Linux

1 The Linux kernel includes the hfsplus module[http://git.kernel.org/?p=linux/kernel

/git/torvalds/linux-2.6.git;a=tree;f=fs/hfsplus;hb=HEAD Git Repository Kernel.org] for mounting HFS+ filesystems read-write. HFS+ fsck and mkfs have been ported to

Linux and are part of the hfsprogs package.[http://packages.debian.org/sid/hfsprogs

User-space supporting tools for HFS+ filesystems under Posix systems.]


BBC Redux - Technical details

1 The fsck-free ZFS file system is used after experiments with Unix File

System (UFS) proved it to be too slow


CHKDSK

1 'CHKDSK' (short for check disk) is a system software|system tool in DOS, OS/2 and Windows. It verifies the file

system integrity of a Volume (computing)|volume and fixes logical file system errors. It is similar to the

fsck command in Unix.


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