[CentOS] xfs not getting it right?

On 20 September 2017 at 10:47, hw <hw at gc-24.de> wrote:
>
> Hi,
>
> xfs is supposed to detect the layout of a md-RAID devices when creating the
> file system, but it doesn´t seem to do that:
>
>
> # cat /proc/mdstat
> Personalities : [raid1]
> md10 : active raid1 sde[1] sdd[0]
>       499976512 blocks super 1.2 [2/2] [UU]
>       bitmap: 0/4 pages [0KB], 65536KB chunk
>
>
> # mkfs.xfs /dev/md10p2
> meta-data=/dev/md10p2            isize=512    agcount=4, agsize=30199892
> blks
>          =                       sectsz=512   attr=2, projid32bit=1
>          =                       crc=1        finobt=0, sparse=0
> data     =                       bsize=4096   blocks=120799568, imaxpct=25
>          =                       sunit=0      swidth=0 blks
> naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
> log      =internal log           bsize=4096   blocks=58984, version=2
>          =                       sectsz=512   sunit=0 blks, lazy-count=1
> realtime =none                   extsz=4096   blocks=0, rtextents=0
>
>
> # mkfs.xfs -f -d su=64m,sw=2 /dev/md10p2
> meta-data=/dev/md10p2            isize=512    agcount=16, agsize=7553024
> blks
>          =                       sectsz=512   attr=2, projid32bit=1
>          =                       crc=1        finobt=0, sparse=0
> data     =                       bsize=4096   blocks=120799568, imaxpct=25
>          =                       sunit=16384  swidth=32768 blks
> naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
> log      =internal log           bsize=4096   blocks=58984, version=2
>          =                       sectsz=512   sunit=8 blks, lazy-count=1
> realtime =none                   extsz=4096   blocks=0, rtextents=0
>
>
> The 64MB chunk size was picked my mdadm automatically.  The device is made
> from two disks, and xfs either doesn´t figure that out, or it decided to
> ignore the layout of the underlying RAID.
>
> Am I doing something wrong here, or is xfs in Centos somehow different?
> Do, or must, we always specify the apporpriate values for su and sw or
> did xfs ignore them because what it picked is better?
>

I don't know enough to answer, but I do have a question.. what were
you expecting xfs to do (and what filesystems do that?) Thanks

-- 
Stephen J Smoogen.