Default helper node

Certain IBM Storage Scale commands that can generate a significant amount of IO, such as file system restripes, adding disks, or policy scans, use helper nodes to run faster.

These nodes can be specified by using the ‘-N’ flag to the command or by using the defaultHelperNode configuration value. Some commands, such as mmapplypolicy, might use more memory or CPU resources while you run to sort file lists. Other commands, such as mmrestripefs, or mmdelsnapshot, might generate a significant amount of IO to move data and update metadata structures. When you specify helper nodes, it is best to ensure that these nodes have sufficient memory, idle CPU, and network to handle these requests. It might be necessary to schedule these commands for a time when the nodes or cluster are not heavily used as well.

Commands that use helper nodes include: mmadddisk, mmapplypolicy, mmbackup, mmchdisk, mmcheckquota, mmdefragfs, mmdeldisk, mmdelsnapshot, mmfileid, mmfsck, mmimgbackup, mmimgrestore, mmrestorefs, mmrestripefs, and mmrpldisk. Helper nodes typically must be separated from the servers that provide storage for IBM Storage Scale RAID.