General Storage Pool Practices

Use whole disks to enable disk write cache and provide easier maintenance. Creating pools on slices adds complexity to disk management and recovery.
Use ZFS redundancy so that ZFS can repair data inconsistencies.
- The following message is displayed when a non-redundant pool is created:
```
$ zpool create system1 c4t1d0 c4t3d0
'system1' successfully created, but with no redundancy; failure
of one device will cause loss of the pool
```
- For mirrored pools, use mirrored disk pairs
- For RAID-Z pools, group 3-9 disks per VDEV
- Do not mix RAID-Z and mirrored components within the same pool. These pools are harder to manage and performance might suffer.
Use hot spares to reduce down time due to hardware failures
Use similar size disks so that I/O is balanced across devices
- Smaller LUNs can be expanded to large LUNs
- Do not expand LUNs from extremely varied sizes, such as 128 MB to 2 TB, to keep optimal metaslab sizes
Consider creating a small root pool and larger data pools to support faster system recovery
Recommended minimum pool size is 8 GB. Although the minimum pool size is 64 MB, anything less than 8 GB makes allocating and reclaiming free pool space more difficult.
Recommended maximum pool size should comfortably fit your workload or data size. Do not try to store more data than you can routinely back up on a regular basis. Otherwise, your data is at risk due to some unforeseen event.