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Re: OT: besser JFS oder XFS ?



Am Mittwoch 27 Februar 2008 schrieb Martin Steigerwald:
> Und es gab da deutliche Verbesserungen in den letzten Kernel-Versionen.
> Insbesondere ein git commit, den ich jetzt aber nicht mehr gefunden
> habe.

Noch besser, da gibts sogar einen FAQ-Eintrag im durchaus lesenswerten 
offiziellen XFS FAQ:

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Q: Why do I see binary NULLS in some files after recovery when I unplugged 
the power? 

Update: This issue has been addressed with a CVS fix on the 29th March 
2007 and merged into mainline on 8th May 2007 for 2.6.22-rc1. 

XFS journals metadata updates, not data updates. After a crash you are 
supposed to get a consistent filesystem which looks like the state 
sometime shortly before the crash, NOT what the in memory image looked 
like the instant before the crash. 

Since XFS does not write data out immediately unless you tell it to with 
fsync, an O_SYNC or O_DIRECT open (the same is true of other 
filesystems), you are looking at an inode which was flushed out, but 
whose data was not. Typically you'll find that the inode is not taking 
any space since all it has is a size but no extents allocated (try 
examining the file with the xfs_bmap(8) command).

http://oss.sgi.com/projects/xfs/faq.html#nulls
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Das finde ich auch sehr schön. Die XFS-Entwickler und SGI gehen mit 
Problemen sehr offen um und helfen auf der XFS-Mailingliste in der Regel 
auch sehr schnell und beantworten Fragen usw.

-- 
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
GPG: 03B0 0D6C 0040 0710 4AFA  B82F 991B EAAC A599 84C7

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