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From: "Leon Kolchinsky" <leonk@construct.haifa.ac.il>
Subject: mkfs and mount tips?
Date: Tue, 13 Feb 2007 10:48:15 +0200
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To: linux-xfs@oss.sgi.com

Hello All, 

I have Pentium II (Deschutes) with first 10GB (/dev/hda) and second
60GB(/dev/hdc) disk. 
After reading gentoo xfs threads on their forum and some SGI docs and FAQs I
came with this options for creating FS and mounting the disks: 

1) To create XFS on hda: 

Code:	
# mkfs.xfs -l internal,size=128m -d agcount=2 /dev/hda	


I've also seen "–d unwritten=0" option: 

So my question: 
Is it safe to add –d unwritten=0 option to increase performance like this
(or will I lose some essential functionality)?: 

Is this how the code should look?:	
# mkfs.xfs -l internal,size=128m -d agcount=2 –d unwritten=0 /dev/hda	


2) To prevent data lost in case of power outage(Disabling the write back
cache): 
Add the following to local.start: 

Code:	
# hdparm -W0 /dev/hda 
# hdparm -W0 /dev/hdc 
# blktool /dev/hda wcache off 
# blktool /dev/hdc wcache off	


Right? 

3) Mount options: 

On gentoo xfs thread it's suggested that the mount options should be
"noatime,logbufs=8" 

But what about "osyncisdsync" mount option. 

"• osyncisdsync 
– Writes to files opened with the O_SYNC flag set will behave as if the
O_DSYNC flag 
had been used instead. 
– This can result in better performance without compromising data safety. 
– However timestamp updates from O_SYNC writes can be lost if the system
crashes. 
Use osyncisosync to disable this setting."

So do you think it is safe to add "osyncisdsync" mount option to fstab? 


I'd appreciate any comments/tips/answers.


Best Regards,
Leon Kolchinsky