ZFS: Grow/Shrink an existing zfs filesystem -

ZFS: Grow/Shrink an existing zfs filesystem

# Tested on RHEL 6 & 7

# Choose the F.S. to resize and verify current size

zfs list
   NAME           USED AVAIL REFER MOUNTPOINT
   c_pool         204K 19.6G    30K /c_pool
   c_pool/zfs01    30K 1024M    30K /zfs01
   c_pool/zfs02    30K 19.6G    30K /filesystem02
   m_pool         100K 9.78G    30K /m_pool

ZPOOL=c_pool
ZFS=zfs01

df -h /$ZFS
   Filesystem            Size Used Avail Use% Mounted on
   c_pool/zfs01          1.0G 128K 1.0G   1% /zfs01

# Extend F.S. to 2GB

zfs set quota=2g $ZPOOL/$ZFS

# Check

zfs list
   NAME           USED AVAIL REFER MOUNTPOINT
   c_pool         204K 19.6G    30K /c_pool
   c_pool/zfs01    30K 2.00G    30K /zfs01
   c_pool/zfs02    30K 19.6G    30K /filesystem02
   m_pool         100K 9.78G    30K /m_pool

df -h /$ZFS
   Filesystem            Size Used Avail Use% Mounted on
   c_pool/zfs01          2.0G 128K 2.0G   1% /zfs01

# Reduce F.S. back to 1GB

zfs set quota=1g $ZPOOL/$ZFS

# Check

zfs list
   NAME           USED AVAIL REFER MOUNTPOINT
   c_pool         204K 19.6G    30K /c_pool
   c_pool/zfs01    30K 1024M    30K /zfs01
   c_pool/zfs02    30K 19.6G    30K /filesystem02
   m_pool         100K 9.78G    30K /m_pool

df -h /$ZFS
   Filesystem            Size Used Avail Use% Mounted on
   c_pool/zfs01          1.0G 128K 1.0G   1% /zfs01

# Here is what happens if we fill up a little bit our filesystem and then try to reduce it
# below the boundary of used space

df -h /$ZFS
   Filesystem            Size Used Avail Use% Mounted on
   c_pool/zfs01          1.0G 350M 675M 35% /zfs01

zfs set quota=256m $ZPOOL/$ZFS
   cannot set property for 'c_pool/zfs01': size is less than current used or reserved space