napp-it ZFS Storage, Руководство пользователя

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9. Create a ZFS datapool
From other systems like Windows, you know disks where you can create one or more partitions with a fixed size.
You can combine single disks or partitions to a Raid that is treated like a single disk. It is possible to increase a
partition up to disk or Raid-array size. But you cannot span a partition afterwards over multiple disks or raid-
arrays without destroying the old partition. If a disk is full, you must create a new one and copy over data.
ZFS allows a more flexible handling of disc capacity with a concept that is called storage virtualization. Base of
this is a storage pool. Unlike a disk or conventional raid array, the size of a ZFS pool can grow dynamically. You
start with a new pool that is build from a Raid-Array example a ZFS Raid-1 or Raid-Z without Raid problems
like the write hole problem of conventional Raid. If you need more capacity, you add more Raid-Arrays to build
storage up to the Petabyte range as this is the real design goal of ZFS.
Similar to oldstyle partitions, you create ZFS filesystems on your pool but unlike old partitions, you do not set a
size of a filesystem as it can grow dynamically up to the poolsize. If you increase the pool, the additional capa-
city is immediately available to all filesystems. You can limit capacity with quotas and ensure with reservations.
create a ZFS pool with menu Pools >> create Pool
- name your pool (ex tank)
- select version (only needed for compatibility mainly with Oracle Solaris and pool v28/5)
- select disks that you want to use for your first raid-array/ vdev (ex two 3 TB disks in a mirror)
- enable overflow protection (a 10% pool reservation that limits usable capacity to prevent a full/slow pool)
You can reduce/ delete the reservation in menu ZFS Filesystems at any time
click submit and your pool „tank„ is created. Details about the pool: see menu Pools
click on poolname to list all pool-properties or on a property to modify.
Extend a ZFS datapool
If you want to increase capacity, use menu Pools >> extend pool and add another Raid-array (ZFS call it vdev)
ex a mirror or raid-Z. ZFS will stripe data over all vdevs to increase not only capacity but performance.