Slower performance with ext4

Mark Kirkwood markir at paradise.net.nz
Mon Nov 2 08:01:27 UTC 2009


Christopher Chan wrote:
>
> No. This is not an insult. You are doing others a disservice by spouting 
> myths. I am now calling your bluff on how different filesystems behave 
> in regards to fsync requests and challenge you to get an authoritative 
> answer from any of the developers of XFS, JFS, ext(x) that contradicts 
> what I has said.
>
>   
No bluff, just no alarmist hype either.

>
> Did you miss my remarks about when you are not using hardware raid + bbu 
> cache? You do know that such hardware covers for any short comings in 
> filesystems with regards to data consistency and that that is the reason 
> for the existence of such hardware?
>
>   

It is (or should be) widely known that cheap (s)ata drives do not honor 
fsync requests (*many* google links).

>
>
> A server motherboard that uses ECC RAM and SAS/SCSI hard drives and 
> software raid will suffer the same results. You have been spouting 
> inaccurate information about filesystem behaviour that will affect those 
> who do not have the means to purchase your uber hardware that covers for 
> any filesystem's shortcomings with respects to data integrity. Others 
> make do with less by having a full understanding of the behaviour of the 
> operating systems they run whether it is FreeBSD and softupdates or 
> Linux and its various filesystems that support journaling. You can get 
> the same data integrity on lesser hardware (motherboards supporting 
> ECC-RAM are no longer the realm of 'server' grade motherboards) if 
> configured properly.
>
>   
No it will not. I've been a Freebsd server admin for the last 10 years - 
no data loss due to power failure on any of my servers - because I've 
used reliable hardware that honors fsync.

regards

Mark




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