Creating Storage Pools
6 minute read.Last Modified 2022-08-03 11:26 EDT
TrueNAS uses ZFS data storage pools to efficiently store and protect data.
It is strongly recommend that you review the available system resources and plan the storage use case before creating a storage pool.
- Allocating more drives to a pool increases redundancy when storing critical information.
- Maximizing total available storage at the expense of redundancy or performance entails allocating large-volume disks and configuring a pool for minimal redundancy.
- Maximizing pool performance entails installing and allocating high-speed SSD drives to a pool.
Determining your specific storage requirements is a critical step before creating a pool.
To create a new pool, go to Storage and click Create Pool.
First, enter a pool name.
Next, configure the virtual devices (vdevs) that make up the pool.
If the disks used have non-unique serial numbers, they do not populate the Available Disks section until you select the Show disk with non-unique serial numbers checkbox.
Clicking Suggest Layout allows TrueNAS to review all available disks and populate the primary Data VDevs with identically sized drives in a configuration balanced between storage capacity and data redundancy. Click Reset Layout to clear the suggestion.
To manually configure the pool, add vdevs according to your use case. Select the Disk checkboxes and click the to move the disks into a vdev.
Warning: USB-connected disks might report their serial numbers inaccurately, making them indistinguishable from each other.
Pools offer several vdev types. Vdevs store data or enable unique features for the pool.
These store data or enable unique features for the pool:
Standard vdev for primary storage operations. Each storage pool requires at least one data vdev. Data vdev configuration typically affects how the other kinds of vdevs get configured.
A Data VDev with disks is duplicated by clicking REPEAT. When more disks are available and equal in size, the REPEAT button creates another vdev with an identical configuration called a mirror of vdevs.
When even more same-size disks are available, you can create multiple copies of the original vdev.
Don’t have multiple data vdevs with different numbers of disks in each vdev. This complicates and limits the pool capabilities.
Hot Spare are drives reserved to insert into Data vdevs when an active drive fails. Hot spares are temporarily used as replacements for failed drives to prevent larger pool and data loss scenarios.
When you replace a failed drive with a new drive, the hot spare reverts to an inactive state and is available again as a hot spare.
If you only detach the failed drive from the pool, the temporary hot spare gets promoted to a full data vdev member and is no longer available as a hot spare.
To add a vdev type during pool creation, click Add Vdev and select the type. Select disks from Available Disks and use the (right arrow) next to the new VDev to add it to that section.
Disks added to a vdev arrange in different layouts, according to the specific pool use case.
We do not recommend mixing disks of different sizes in a vdev. If you do, you must Force the action and override the One or more data vdevs has disks of different sizes error.
Each disk stores data. Requires at least one disk and has no data redundancy.
Never use a Stripe type vdev to store critical data! A single disk failure results in losing all data in the vdev.
The Pool Manager suggests a vdev layout from the number of disks added to the vdev. For example, if you add two disks, TrueNAS automatically configures the vdev as a Mirror. The total available storage is the size of one added disk while the other disk provides redundancy.
To change the vdev layout, open the Data VDevs list and select the desired layout.