Recommended best practices for large files on OneFS include:
- Only enable large file support if you are planning to store files larger than 4 TiB.
- Ensure that the cluster, including any individual node pools, is less than 85 percent full, so performance is not affected and that adequate space is always available for large file creation, repair, and restriping.
- Always keep OneFS virtual hot spare (VHS) enabled to reserve space in case you need to smartfail devices. However, be aware that all VHS reserved space will be subtracted from the isi_large_file usable capacity metrics and will affect cluster sizing requirements.
- Large file support is available in OneFS 8.2.2 and later and accommodates individual files up to 16 TiB.
- Once large file support has been enabled on a cluster, it cannot be undone or disabled. This has a particular significance for SyncIQ replication environments.
- A maximum sized file (16 TiB) + protection can consume no more than 10 percent of any disk pool. This translates to a minimum disk pool size of 160 TiB + protection.
- After large file support is enabled, the “cluster full” alert threshold is automatically lowered to 85 percent from the default of 95 percent to warn against low-space conditions.
- The isi_large_file -c command is used to check that certain requirements are met on a cluster before the large file support feature can be enabled. Once the feature is enabled, files larger than 4 TiB files may exist on the system.
- The maximum size of alternate data streams (ADS) remains at 4 TiB.
- All SyncIQ remote clusters described in existing SyncIQ policies must be running version 8.2.2 or later and also satisfy the restrictions for minimum disk pool size and SyncIQ policies.
- All SyncIQ policies only connect with clusters that have large file support enabled. SyncIQ policies will fail upon a connection attempt to a cluster that does not have large file support enabled.
- Failure to install and commit the OneFS 8.2.2 or later release and to enable the large file support feature on all SyncIQ partner clusters can result in the failure of SyncIQ policies.