2.2.2. Exercise 2

Make an XFS filesystem to contain many small files per directory

reduce filesystem block size to 512 bytes to save wasted space
use the maximum directory block size of 4KB (this is actually the default), this allows for more entries per level in the directory b-trees resultling in faster lookups.

Create the filesystem.

# mkfs -t xfs -f -b size=512 -n size=4096 /dev/sda4
meta-data=/dev/sda4              isize=256    agcount=16, agsize=3692941 blks
         =                       sectsz=512   attr=0
data     =                       bsize=512    blocks=59087056, imaxpct=25
         =                       sunit=0      swidth=0 blks, unwritten=1
naming   =version 2              bsize=4096
log      =internal log           bsize=512    blocks=28851, version=1
         =                       sectsz=512   sunit=0 blks
realtime =none                   extsz=65536  blocks=0, rtextents=0
# mount /dev/sda4 /mnt
# cd /mnt
# for file in `seq 0 1000`; do echo $file > $file; done
# du -k
537     .

Try the same test with a default block size of 4KB and verify the savings for yourself.