>> Has anyone tuned XFS with its several mount options?

some useful info below, which I didn't know (logbsize & delaylog).  I suspect 
it  
would increase backuppc performance.  

http://xfs.org/index.php/XFS_FAQ:

> Q: I want to tune my XFS filesystems for <something>
> 
> The standard answer you will get to this question is this: use the defaults.
> 
> There are few workloads where using non-default mkfs.xfs or mount
> options make much sense. In general, the default values already
> used are optimised for best performance in the first place. mkfs.xfs
> will detect the difference between single disk and MD/DM RAID setups
> and change the default values it uses to configure the filesystem
> appropriately.
> 
> There are a lot of "XFS tuning guides" that Google will find for
> you - most are old, out of date and full of misleading or just plain
> incorrect information. Don't expect that tuning your filesystem for
> optimal bonnie++ numbers will mean your workload will go faster.
> You should only consider changing the defaults if either: a) you
> know from experience that your workload causes XFS a specific problem
> that can be worked around via a configuration change, or b) your
> workload is demonstrating bad performance when using the default
> configurations. In this case, you need to understand why your
> application is causing bad performance before you start tweaking
> XFS configurations.
> 
> In most cases, the only thing you need to to consider for mkfs.xfs
> is specifying the stripe unit and width for hardware RAID devices.
> For mount options, the only thing that will change metadata performance
> considerably are the logbsize and delaylog mount options. Increasing
> logbsize reduces the number of journal IOs for a given workload,
> and delaylog will reduce them even further. The trade off for this
> increase in metadata performance is that more operations may be
> "missing" after recovery if the system crashes while actively making
> modifications.


One other thing that I found while poking around is references to "lazy 
counters."  
This is a newer feature of XFS and should increase performance from what i can 
tell.  
If you make a filesystem with the current version of XFS tools it will be on by 
default.  
Make sure that your system is using the current version - see the mkfs.xfs man
page for more.

If you have an existing XFS filesystem it probably isn't on, but it appears you 
may be able to 
change that with xfs_util.   

I would make sure I had a backup of the filesystem before dorking with 
xfs_util.  

hope this helps

danno
--
Dan Pritts, Sr. Systems Engineer
Internet2
office: +1-734-352-4953 | mobile: +1-734-834-7224


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