PeerCache uses virtual workspaces for both your managed and unmanaged data. The file data is separated into two layers as part of creating the virtual workspace: The descriptive file metadata (file name, size, owner, group, mask, create/access/modify time…), and the file content with all the actual bytes your EDA tools need.
These virtual workspaces require much less disk storage than multiple physical copies do.
First, virtual workspaces eliminate the need to make physical copies of your design’s source and derived data files. Instead, when you create multiple new workspaces, you avoid duplication. This is because rather than copying the entire file tree, we only copy the metadata, and then point to the same set of common files, so that all the workspaces on a given host share the same common files.
- The core design is an invariant copy that doesn’t change.
- Only the metadata changes and per workspace changes require additional storage. If you are using a DM system, once those changes are checked in, the space is automatically freed up.
With Virtual Workspaces, any duplication is in the caches, and not in the NFS filer’s authoritative data. This combination reduces NFS filer storage by 90 percent.
In figure 2 below, you can see a visual representation of the filer reduction from PeerCache virtual workspaces as compared with traditional workspaces that require physical copies.