Issue

• According to 'man mkfs.xfs', it says that block size can be specified up to 65536.

$ man mkfs.xfs
  :
  -b block_size_options
         This option specifies the fundamental block size of the filesys‐
         tem.   The valid block_size_options are: log=value or size=value
         and only one can be  supplied.   The  block  size  is  specified
         either as a base two logarithm value with log=, or in bytes with
         size=.  The default value is 4096 bytes (4 KiB), the minimum  is
         512,  and the maximum is 65536 (64 KiB).  XFS on Linux currently
         only supports pagesize or smaller blocks.
  :

• We confirmed that it could be specified up to 65536 (see below). However, it also says XFS on Linux currently only supports pagesize or smaller blocks.

[root@RHEL7U1 ~]# mkfs -t xfs -f -s size=4096 -b size=16384 /dev/sdb1
meta-data=/dev/sdb1              isize=256    agcount=4, agsize=16368 blks
         =                       sectsz=4096  attr=2, projid32bit=1
         =                       crc=0        finobt=0
data     =                       bsize=16384  blocks=65472, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=16384  ascii-ci=0 ftype=0
log      =internal log           bsize=16384  blocks=512, version=2
         =                       sectsz=4096  sunit=1 blks, lazy-count=1
realtime =none                   extsz=16384  blocks=0, rtextents=0

[root@RHEL7U1 ~]# mkfs -t xfs -f -s size=4096 -b size=32768 /dev/sdb1
meta-data=/dev/sdb1              isize=256    agcount=4, agsize=8184 blks
         =                       sectsz=4096  attr=2, projid32bit=1
         =                       crc=0        finobt=0
data     =                       bsize=32768  blocks=32736, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=32768  ascii-ci=0 ftype=0
log      =internal log           bsize=32768  blocks=512, version=2
         =                       sectsz=4096  sunit=1 blks, lazy-count=1
realtime =none                   extsz=32768  blocks=0, rtextents=0

[root@RHEL7U1 ~]# mkfs -t xfs -f -s size=4096 -b size=65536 /dev/sdb1
meta-data=/dev/sdb1              isize=256    agcount=4, agsize=4092 blks
         =                       sectsz=4096  attr=2, projid32bit=1
         =                       crc=0        finobt=0
data     =                       bsize=65536  blocks=16368, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=65536  ascii-ci=0 ftype=0
log      =internal log           bsize=65536  blocks=512, version=2
         =                       sectsz=4096  sunit=1 blks, lazy-count=1
realtime =none                   extsz=65536  blocks=0, rtextents=0

[root@RHEL7U1 ~]# mkfs -t xfs -f -s size=4096 -b size=131072 /dev/sdb1
illegal block size 131072
Usage: mkfs.xfs
:

• Does it mean as it shows redhat also does not support XFS if block size exceeds pagesize even though it can be specified beyond pagesize?