Before performing an expansion, you must understand the options and limitations of each type of expansion.
Adding storage volumes to virtual Storage Nodes
You can increase the overall storage capacity of your grid by adding additional storage volumes (LUNs) to existing non-appliance Storage Nodes. You cannot expand the storage capacity of an appliance Storage Node. The maximum storage available on each StorageGRID Webscale appliance Storage Node is fixed, based on the appliance model and original configuration.
When preparing to add storage volumes, be aware of the following limitations:
- Each node can support a maximum of 16 storage volumes. If you need to add capacity beyond that, you must add new Storage Nodes.
- You cannot add storage volumes to a Storage Node at the same time you are performing a system upgrade or recovery operation.
- Before adding storage volumes, you must review the active information lifecycle management (ILM) policy and rules. In most cases, you must add storage volumes to more than one Storage Node to satisfy ILM requirements for replicated or erasure-coded copies.
See "Adding storage volumes to Storage Nodes" for instructions.
Adding grid nodes to an existing site
You can expand storage capacity and add redundancy to a
StorageGRID Webscale system by adding new grid nodes to an existing data center site. You can add one or more of the following types of nodes in a single expansion:
- Non-primary Admin Nodes
- Storage Nodes
- Archive Nodes
- API Gateway Nodes
When preparing to add grid nodes, be aware of the following limitations:
- The primary Admin Node is deployed during the initial installation. You cannot add a primary Admin Node during an expansion.
- Before adding Storage Nodes, you must review the active ILM policy and rules and the StorageGRID Webscale system’s current topology.
- If an ILM rule creates replicated copies, you must consider the number of copies created and how they are distributed to storage pools. For example, if an ILM rule creates one replicated copy at data center site 1 (DC1) and one copy at data center site 2 (DC2), you must add an equivalent number of Storage Nodes at each site to increase the overall capacity of the StorageGRID Webscale system.
- If you are using or want to use erasure coding, you must understand the Storage Node and site requirement for the erasure coding scheme you want to use. If you are adding Storage Nodes because the system's existing Storage Nodes are nearing capacity, you must add enough Storage Nodes to support the erasure coding scheme in use. See the ILM section of the Administrator Guide to learn the requirements for each supported erasure coding scheme.
- If you are adding Archive Nodes, note that each Archive Node supports one interface, either tape through Tivoli Storage Manager (TSM) middleware or the cloud through the S3 API.
See "Adding grid nodes to an existing site or adding a new site" for instructions.
Adding data center sites
You can expand your StorageGRID Webscale system by adding a new data center site.
When preparing to add a data center site, be aware of the following limitations:
- You can only add one data center site per expansion operation.
- You cannot add grid nodes to an existing data center site as part of the same expansion.
- The new data center site must include at least three Storage Nodes.
- Because your StorageGRID Webscale system remains operational during the expansion, you must review ILM rules before starting the expansion procedure. You must ensure that object copies are not stored to the new data center site until the expansion procedure is complete. For more information about ILM rules, see the Administrator Guide.
- When you add a new site, a copy of the Cassandra database (used for object metadata) is saved to the Storage Nodes at the new site. For this reason, adding a new site does not increase the number of objects you can store in the grid. To increase the maximum number of objects you can store in your StorageGRID Webscale system, you must increase the number of Storage Nodes per site, which increases the amount of space available for object metadata.
See "Adding grid nodes to an existing site or adding a new site" for instructions.