XFS: Abysmal write performance because of excessive seeking (allocation groups to blame?)

[Stefan Ring]

> And is XFS aligned to the RAID 6?
>
> What does xfs_info display on it?

Yes, it’s aligned.

meta-data=/dev/mapper/vg_data-lvhome isize=256    agcount=4,
agsize=73233656 blks
         =                       sectsz=512   attr=2
data     =                       bsize=4096   blocks=292934624, imaxpct=5
         =                       sunit=8      swidth=32 blks
naming   =version 2              bsize=4096   ascii-ci=0
log      =internal               bsize=4096   blocks=143040, version=2
         =                       sectsz=512   sunit=8 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0

I changed the stripe size to 32kb in the meantime. This way, it
performs slightly better.