Re: Looking for advice on creating XFS on a large (to me) RAID

[Christoph Hellwig <hch@infradead.org>]

On Thu, Nov 03, 2011 at 12:29:58PM -0400, Krzysztof Adamski wrote:
> Hi All,
> 
> I'm about to create a XFS file system on a MD RAID6 made up of 12 3T
> drives.
> 
> This is the command line that I was planning to use:
> 
> # mkfs.xfs

> -l lazy-count=1

This is the default in any semi-recent xfsprogs version.

> -s size=4096

using a sector size larger than the actual disk sector size might risk
data loss, as the log code expects sector sized writes to be atomic.

If you have a real 4k logical sector disk it should be picked up
automatically with the kernel topology support.  We don't quite do the
right thing for 512 byte logical / 4k physical disks, in which case
you might need this line.

> -N

That won't actually create you a filesystem :)

>          =                       sunit=128    swidth=1280 blks

In general you're better off with a 32k stripe unit / chunk size,
than the extremly large default of 512k.

> Should I change any default parameters to mkfs.xfs

Usually not.