Does RHEL support local filesystems with block size larger than 4KB?

Issue

• We want to have a block-size of 8192 on a local filesystem such as Ext4 or XFS.
• Can we create an Ext4 or XFS filesystem with a block size greater than 4KiB (4096 bytes)?
• What is the maximum supported Ext3, Ext4 block size in RHEL?
  • Why can't I mount a ext4 filesystem with blocksize larger than 4 KiB?

• After creating an ext4 filesystem with a blocksize larger than 4KiB, the message following error message returns when I try to mount it:

          # mount -t ext4 /dev/sda1 /mnt
          mount: wrong fs type, bad option, bad superblock on /dev/sda1,
             missing codepage or helper program, or other error
           In some cases useful info is found in syslog - try
             dmesg | tail  or so.
  
          # dmesg | tail 
          EXT4-fs (sda1): bad block size 32768
  

• What is the maximum supported XFS block size in RHEL?

  • What is the maximum pagesize supported by XFS?
  • 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 filesystem
                 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:

  # 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
  
  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
  
  # 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
  
  # 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 Red Hat also does not support XFS if block size exceeds pagesize even though it can be specified beyond pagesize?