Slower performance with ext4

Ong Raphael raphaelong1996 at yahoo.com.sg
Mon Nov 2 06:47:31 UTC 2009



So, is the conclusion that ext4 sucks and ext3 rocks in performance wise?


________________________________
From: Christopher Chan <christopher.chan at bradbury.edu.hk>
To: "Ubuntu user technical support, not for general discussions" <ubuntu-users at lists.ubuntu.com>
Sent: Monday, 2 November 2009 1:49:48
Subject: Re: Slower performance with ext4

Mark Kirkwood wrote:
> Christopher Chan wrote:
>  
>> Journaling only for metadata is not 'as much journaling as any other 
>> canditates.' You cannot say metadata journaling only as equivalent to 
>> the data and metadata journaling that is possible with ext3. XFS's 
>> journaling only provides filesystem metadata consistency which is why 
>> you get files full of NULLs after a crash/power out. MTAs rely on fsync 
>> calls and how a filesystem behaves in regards to fsync requests is the 
>> real determiner of whether there is a data guarantee or not. XFS does 
>> not provide data guarantee. It, at best, provides a metadata guarantee. 
>> XFS should not be used for mta queues unless it is in conjunction with 
>> hardware raid that has a bbu cache. XFS is best suited for streaming 
>> applications where the data loss is tolerated.
>>
>>  
>>    
> Sorry, but that is completely incorrect. Applications that use fsync are 
> safe with any filesystem - fsync forces the modified buffers to *disk*, 
> so all discussions about os and filesystem caching are irrelivant[1].
>  

Yes...where *disk* = journal. Which for JFS, XFS and ext3 data=ordered 
means metadata only. Only ext3 data=journal guarantees data and 
metadata. Feel free to get (whoever filesystem developer) to confirm for 
me because you won't get any other answer than what I have just posted.

-- 
ubuntu-users mailing list
ubuntu-users at lists.ubuntu.com
Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-users



      New Email names for you! 
Get the Email name you've always wanted on the new @ymail and @rocketmail. 
Hurry before someone else does!
http://mail.promotions.yahoo.com/newdomains/sg/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.ubuntu.com/archives/ubuntu-users/attachments/20091102/7a206526/attachment.html>


More information about the ubuntu-users mailing list