ndb_restore — Restore an NDB Cluster Backup Maximum Value 1024 When restoring a backup by slices, this option sets the number of slices into which to divide the backup. This allows multiple instances of  ndb_restore  to restore disjoint subsets in parallel, potentially reducing the amount of time required to perform the restore operation. A  slice  is a subset of the data in a given backup; that is, it is a set of fragments having the same slice ID, specified using the  --slice-id  option. The two options must always be used together, and the value set by  --slice-id  must always be less than the number of slices. ndb_restore  encounters fragments and assigns each one a fragment counter. When restoring by slices, a slice ID is assigned to each fragment; this slice ID is in the range 0 to 1 less than the number of slices. For a table that is not a  BLOB  table, the slice to which a given fragment belongs is determined using the formula shown here: For a  BLOB  table, a fragment counter is not used; the fragment number is used instead, along with the ID of the main table for the  BLOB  table (recall that  NDB  stores  BLOB  values in a separate table internally). In this case, the slice ID for a given fragment is calculated as shown here: Thus, restoring by  N  slices means running  N  instances of  ndb_restore , all with  --num-slices= N (along with any other necessary options) and one each with  --slice-id=1 ,  --slice-id=2 ,  -- slice-id=3 , and so on through  slice-id= N -1 . Example.   Assume that you want to restore a backup named  BACKUP-1 , found in the default directory /var/lib/mysql-cluster/BACKUP/BACKUP-3  on the node file system on each data node, to a cluster with four data nodes having the node IDs 1, 2, 3, and 4. To perform this operation using five slices, execute the sets of commands shown in the following list: 4383 shell>  ndb_restore shell>  ndb_restore shell>  ndb_restore shell>  ndb_restore shell>  ndb_restore shell>  ndb_restore shell>  ndb_restore shell>  ndb_restore shell>  ndb_restore shell>  ndb_restore shell>  ndb_restore shell>  ndb_restore shell>  ndb_restore shell>  ndb_restore shell>  ndb_restore shell>  ndb_restore shell>  ndb_restore shell>  ndb_restore 2. Restore the cluster data to the data nodes invoking  ndb_restore  as shown here: 1. Restore the cluster metadata using  ndb_restore  as shown here: shell>  ndb_restore -b 1 -n 1 -m --disable-indexes --backup-path=/home/ndbuser/backups [ slice_ID ] = ([ main_table_ID ] + [ fragment_ID ]) % [ number_of_slices ] [ slice_ID ] = [ fragment_counter ] % [ number_of_slices ]