US Patent 10114754 Techniques for space reservation in a storage environment

Improved techniques and systems are disclosed for ensuring that physical storage is available for cached allocating writes in a thinly provisioned storage environment. By monitoring the size of the cached allocating writes in the file system cache and taking cache occupancy reduction actions when criteria for cache reduction are fulfilled, caching of allocating writes that do not have a corresponding physical storage allocation can be eliminated or reduced to a user-configurable maximum without disabling caching of allocating writes. Using these techniques, allocating writes may be cached without risk of data loss.