Write Ahead Physical Block Logging

__NOTOC__ '''Write Ahead Physical Block Logging''' (WAPBL) provides meta data journaling for file systems in conjunction with Fast File System (FFS) to accomplish rapid filesystem consistency after an unclean shutdown of the filesystem and better general use performance over regular FFS.{{r|w|b-n-w|wapbl.4|wapbl.9}} With the journal, fsck is no longer required at system boot; instead, the system can replay the journal in order to correct any inconsistencies in the filesystem if the system has been shut down in an unclean fashion.{{r|wapbl.4}}

== History ==

WAPBL was initially committed into NetBSD in 2008, and first appeared with NetBSD 5.0 (2009).{{r|wapbl.h|b-n-w|n50}}

With NetBSD 6.0 (2012), ''soft updates'' (known as ''soft dependencies'' in NetBSD) was removed in favour of ''WAPBL''.{{r|n60|softdep_rm}}

== See also == {{Portal | Free and open-source software }} * Log-structured file system * Soft updates * Unix File System (UFS/FFS)

== References == {{Reflist |refs=

<ref name=w>{{cite web |author= Wasabi Systems Inc. |date= 2008 |url= http://www.wasabisystems.com/technology/wjfs |title= Wasabi JFS |archive-url= https://web.archive.org/web/20080306194749/http://www.wasabisystems.com/technology/wjfs |archive-date= 2008-03-06 }}</ref>

<ref name=b-n-w>{{cite web |url= http://broadcast.oreilly.com/2009/05/netbsd-wapbl.html |title= NetBSD WAPBL |author= Federico Biancuzzi |publisher= O'Reilly Media |date= 2008-05-18 |archive-url= https://web.archive.org/web/20100107141731/http://broadcast.oreilly.com/2009/05/netbsd-wapbl.html |access-date=2019-03-24 |archive-date= 2010-01-07 }}</ref>

<ref name=wapbl.h>{{cite web |author= The NetBSD Foundation, Inc. |date= 2008 |url= http://bxr.su/n/sys/sys/wapbl.h |title= sys/wapbl.h |website= BSD Cross Reference |publisher= NetBSD }}</ref>

<ref name=wapbl.4>{{cite web |author= The NetBSD Foundation, Inc. |date= 2008–2012 |url= http://bxr.su/n/share/man/man4/wapbl.4 |title= WAPBL(4) — Write Ahead Physical Block Logging file system journaling |website= BSD Cross Reference |publisher= NetBSD }}</ref>

<ref name=wapbl.9>{{cite web |author= The NetBSD Foundation, Inc. |date= 2015 |url= http://bxr.su/n/share/man/man9/wapbl.9 |title= WAPBL(9) — write-ahead physical block logging for file systems |website= BSD Cross Reference |publisher= NetBSD }}</ref>

<ref name=n50>{{cite web |author= The NetBSD Project |date=2009-04-29 |url= //www.netbsd.org/releases/formal-5/NetBSD-5.0.html |title= Announcing NetBSD 5.0 |publisher= NetBSD |quote= Some highlights are: a preview of metadata journaling for FFS file systems (known as WAPBL, Write Ahead Physical Block Logging) }}</ref>

<ref name=n60>{{cite web |author= The NetBSD Project |date=2012-10-17 |url= //www.netbsd.org/releases/formal-6/NetBSD-6.0.html#removals |title= Components removed from NetBSD |work= Announcing NetBSD 6.0 |publisher= NetBSD |quote= "softdep" support is no longer available in FFS; use wapbl(4) logging instead. }}</ref>

<ref name=softdep_rm>{{cite web |author= Adam Hamsik |date=2009-02-23 |url= //blog.netbsd.org/tnf/entry/soft_dependencies_removed |title= Soft dependencies removed |publisher= NetBSD }}</ref>

}}

== External links == {{div col |colwidth=8em}} * {{URL|http://bxr.su/n/sys/sys/wapbl.h|sys/wapbl.h}} * {{URL|http://mdoc.su/n/wapbl.4|wapbl(4)}} * {{URL|http://mdoc.su/n/wapbl.9|wapbl(9)}} {{div col end}}

Category:Computer file systems Category:Disk file systems Category:NetBSD Category:Unix file system technology