Hello XFS list,
I am trying to figure out the optimal mkfs settings for a large array (i.e., 18
TB) consisting of 2 or 4 PHYSICAL 3ware RAID-5 arrays striped together with
Linux software RAID-0. As far as I can tell, this question about combining
physical and software RAID has not been asked or answered on the list.
As I understand it, for a SINGLE 12-drive 3ware PHYSICAL Hardware RAID-5
created with a 3-ware-defined "stripe size" of 64K, the optimal mkfs setting
should be:
mkfs.xfs â??d su=64k,sw=11 /dev/sdX
The question is, what is optimal if I stripe together TWO of these Physical
Hardware RAID-5 arrays as a SOFTWARE RAID-0. Casual testing shows striping
together two PHYSICAL RAIDS as sucn can yield a gain in performance of
approximately 60 percent versus 12-drives. But in order to optimize the RAID-0
device, would the correct mkfs be:
mkfs.xfs -d su=64k,sw=22 /dev/mdX
There are now 24 drives minus two for parity. Is the logic correct here?
Regards,
Andrew
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