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SubjectHow do I tell if my partition is aligned for a 64k/RAID-6?
Output:

===============================================================================

p34:~# parted /dev/sda print unit s print unit chs print
Model: AMCC 9650SE-16M DISK (scsi)
Disk /dev/sda: 13.0TB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number Start End Size File system Name Flags
1 17.4kB 13.0TB 13.0TB xfs

Model: AMCC 9650SE-16M DISK (scsi)
Disk /dev/sda: 25390350336s
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number Start End Size File system Name Flags
1 34s 25390350302s 25390350269s xfs

Model: AMCC 9650SE-16M DISK (scsi)
Disk /dev/sda: 1580476,53,56
Sector size (logical/physical): 512B/512B
BIOS cylinder,head,sector geometry: 1580476,255,63. Each cylinder is 8225kB.
Partition Table: gpt

Number Start End File system Name Flags
1 0,0,34 1580476,53,23 xfs

p34:~#

===============================================================================

I created a partition from 0Gb to 13T on the following LUN, but how do I
verify this is aligned to the (hardware) 64KiB raid-6 array?

Unit UnitType Status %RCmpl %V/I/M Stripe Size(GB) Cache AVrfy
------------------------------------------------------------------------------
u0 RAID-6 OK - - 64K 12107.1 ON ON

===============================================================================

p34:~# xfs_info /dev/sda1
meta-data=/dev/sda1 isize=256 agcount=12, agsize=268435455
blks
= sectsz=512 attr=2
data = bsize=4096 blocks=3173793783, imaxpct=5
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096
log =internal bsize=4096 blocks=32768, version=2
= sectsz=512 sunit=0 blks, lazy-count=0
realtime =none extsz=4096 blocks=0, rtextents=0

===============================================================================

I am not worried about the filesystem as the defaults usually get it right
but with parted, this is the first time I had to use it for home use and
with RAID-6 I am noticing slower performance with 15 disks (1 is a spare)
in RAID-6 (albeit slower 7200 ones, RE3s) than I was getting with 10
raptor150s in RAID-6 (but I had used fdisk there).

Justin.



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