Where is the data stored in a Metrocluster configuration?

[Msan]

We are using a 4 node Metrocluster FC config with Synchronous Mirror. If we are not mistaken, this means that the active data from the primary side is replicated to the secondary(dormant) side on the fly.

On the secondary side, we are able to see the SVM-mcs and Volume-mcs, but the volumes does not show any used size information or anything like that... basically no data is available about how much data is really here!? How much capacity is being taken?

When the capacity of the aggregate is checked for used space it only shows the amount of data that is stored in the live/active volumes and does not show any data present in the Volumes-mc.

Is the data replicated to the secondary side of the Metrocluster really there? If so, then why and how is it not considered when querying for used space of a given aggregate? In case the mirrored data is not calculated in the used capacity of the aggregate, does that imply that neither sides of the Metrocluster should contain over 45% of used capacity, otherwise in case of a switchover the used capacity would be over 90% or even above 100%, leaving the up-side of the switchover disfunctional?

Thanks for any efforts spared for answering!

[Sanaman · Accepted solution]

Hi,

1. If you have a metro cluster with two sites and each site provision 100TB storage. That 100TB is mirrored to other site (If you run sysconfig -r, you will see aggregate is mirrored). So each site is actually have storage provisioning of 200TB (active + dormant). 100TB of partner (active side) size is not visible on partner (dormant) side. When metro is built each site must have catered for 200TB (own+partner).

2) When switchover happens storage space wise there shouldn't be an issue if the metro storage was planned as per above. Only concern will be the load (CPU and others) because one site will be handling two sites workloads.

Hope that make scene.

[Msan]

Thanks a lot Sanaman!

Yesterday by the end of the day I looked into disks and owners, that revealed that each site caters for double amount of disks that are used and visible in general.