CDOT Tips: InterCluster LIFs

When you see ICL or “InterCluster LIF,” think SnapMirror/SnapVault.  ICL’s are interfaces totally dedicated to replication between clusters, that’s all they can do.  Here’s a couple important things to think about:

1.       There are two kinds of replication in CDOT:

a.       IntraCluster: this means volume move from one node to the other within the cluster.  This occurs using SnapMirror via the private 10Gb cluster network.

b.      InterCluster: This means SnapMirror or SnapVault to another cluster, which occurs over TR’s shared network.

2.     All of a cluster’s SnapMirror and SnapVault to other clusters only occur via the ICL’s. 

3.       ICLs work on two kinds of ports: Role=Data or Role=InterCluster.  Remember, you can assign a role to a port so that only LIFs with compatible roles will ever land there.

4.       Create at least 1 ICL per node.  ICL’s can’t be failed over between nodes, they are dedicated to that node.

5.       In 8.2, a node’s ICL’s can only be in a single network.   In 8.3 IPSpaces are re-introduced and allow multiple ICL’s in multiple IPSpaces per node.

CDOT Tips: Replication

Following the “Data has mass” train of thought, here’s how we move and protect data in CDOT.  We have three types of replication:

•           SyncMirror: Synchronous replication.  For redundancy.
•           SnapMirror (DP): Replication to a 1-minute granularity.  For disaster recovery.
•           SnapVault (XDP): Replication to a 1-hour granularity.  Think backups.

In CDOT we’ve simplified the commands and protocol: to create a SnapVault relationship, you run “SnapMirror create –type XDP.”  To create a SnapMirror relationship, you run “SnapMirror create –type DP.”  Here’s an example of setting up SnapMirror via CLI.

vs2::> snapmirror create -destination-path vs2:dept_eng_dp_mirror2 -source-path vs1:dept_eng -type DP

The primary distinction between DP SnapMirror and XDP SnapMirror is that SnapVault allows you to keep more snapshots on the destination.  Essentially, XDP SnapMirror is for long-term backups.  Other differences:

•           DP SnapMirror relationships can be reversed (swap destination and source)
•           DP SnapMirror can replicate every minutes, XDP SnapMirror once per hour.
•           DP SnapMirror destination volumes can be made read/write.

Do you have some datasets that would benefit from a quicker time to recovery or have stricter SLA’s?  If so, DP SnapMirror is the best choice.    Now, with many systems and many volumes being replicated, how do you keep track of it all?  In our no-cost tool OCUM 6.0, there is a “Protection” tab that allows you to setup, change, remove, restore, and monitor all your replication relationships. 

Because ONTAP is our single-platform operating system, this also means you can replicate to the cloud (Cloud ONTAP in AWS or Azure), to an all-SATA NetApp “backup” system, or any other NetApp you have.  This “ONTAP everywhere” ubiquity is part of why ONTAP manages more exabytes than any other storage operating system in the world.