ONTAP Discussions

ONTAP Select 9.x best practice for aggregate creation


From ONTAP Select document and TR-4517, I have following understanding:


  1. General guidance of single–RAID group/single-LUN from underlying server DAS
    • LUN size limit by hypervisor extent limitation (64TB)
    • Create multiple equal-sized LUNs if limit reached, then provision the vSphere datastore using all attached LUNs
    • ONTAP Select receives no performance benefits by increasing the number of LUNs within the RAID group. Adding additional LUNs should only be done to bypass hypervisor file system limitations.
  2. After ONTAP select VM is deployed and root disks provisioned, the underlying attached storage is breaks up the into even number set of equal-sized virtual disks, each not exceeding 8TB
    • Similar to creating multiple LUNs, ONTAP Select receives no performance benefits by increasing the number of virtual disks used by the system.
  3. When the second RAID group is added (server DAS), a second LUN must be provisioned and should be added as a new extent to the existing datastore.
    • NetApp recommends that newly attached storage be added to the existing datastore as a new extent, rather than configured as a second datastore on the system.
    • the newly assigned storage should be split into an even number set of equal-sized virtual disks, not exceeding 8TB
    • Currently, the ONTAP Deploy tool does not support the workflow of adding space to a Select node, so this process must be done using the native vSphere tooling.
  4. For four node ONTAP select cluster, all aggregate is RAID 0 and must be mirrored.
    • maximum aggregate size is 100TiB
    • maximun volume size is 60TiB

My question are:

  1. Can I create aggreate with more than 2 disks (X = even mumber)? 
    • this means X/2 number of raidgroup in each plex? (one raidgroup per disk)
    • Will there be any performance penalty?
  2. If I increased the underlying datastore size and created more virtual disk, can I add the disks to the existing aggregate?
    • what are the consideration?