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To use ZFS, at least 1 GB of memory is recommended (for all architectures) but more is helpful as ZFS needs *lots* of memory. Depending on your workload, it may be possible to use ZFS on systems with less memory, but it requires careful tuning to avoid panics from memory exhaustion in the kernel.
A 64-bit system is preferred due to its larger address space and better performance on 64-bit variables, which are used extensively by ZFS. 32-bit systems are supported though, with sufficient tuning.
ZFS Administration Considerations
ZFS Storage Pools Recommendations
This section describes general recommendations for setting up ZFS storage pools.
System/Memory/Swap Space
- Run ZFS on a system that runs a 64-bit kernel
- One GB or more of memory is recommended.
- Approximately 64 KB of memory is consumed per mounted ZFS file system. On systems with 1,000s of ZFS file systems, provision 1 GB of extra memory for every 10,000 mounted file systems including snapshots. Be prepared for longer boot times on these systems as well.
- Size memory requirements to actual system workload:
- With a *known* application memory footprint, such as database application, you might cap the ARC size so that the application will not need to reclaim its necessary memory from the ZFS cache.
- Identify ZFS memory usage with memstat
- Consider dedup memory requirements