Add new zvol

This function allows you to create a new zvol. You have to fill in or choose detailed information related to zvol :

• Name - Name of the new Zvol
• Size - Size of the new Zvol. The unit for this values is GiB (Gibibyte).
  In general, if you multiply 1024 ·1024 ·1024 = 1 073 741 824b, the result is equal to 2³⁰.
  For example, 1 GiB = 1024 × 1 MiB = 1024 × 1024 × 1 KiB = 1024 × 1024 × 1024 × 1 B = 1 073 741 824 ~ 1070 GB

• Provisioning:*​Thin provisioned - involves using virtualization technology to give the appearance of having more physical resources than are actually available. Use this format to save storage space. For the thin disk, you provision as much datastore space as the disk would require based on the value that you enter for the disk size. However, the thin disk starts small and at first, uses only as much datastore space as the disk needs for its initial operations.
  • Thick provisioned (default) - creates a virtual disk in a thick format. Space required for the virtual disk is allocated when the virtual disk is created. Data remaining on the physical device is not erased during creation.

• Deduplication:*​Disabled (default)
  • On - is a pseudonym for "sha256"
  • Verify - is a pseudonym for "sha256,verify", option that performs a full comparison of every incoming block with any alleged duplicate to ensure that they really are the same
  • sha256 - performs an operation where the same output given two different inputs, then it is reasonable to assume that when two blocks have the same checksum, they are in fact the same block.
  • sha256, Verify - enables an ability to detect and correct hash collisions, however this is very system intensive and is not recommended for casual use

• ​COPIES - Controls the number of copies of data stored for this dataset. These copies are in addition to any redundancy provided by the pool, for example, mirroring or raid-z. The copies are stored on different disks, if possible. The space used by multiple copies is charged to the associated file and dataset, changing the "used" property and counting against quotas and reservations. Changing this property only affects the newly-written data. You can choose from three options:
  • 1 (default)
  • 2
  • 3

• Compression - there are several data compression methods - You will see all available methods on the drop-down list. The default compression method is lz4.You can also choose no compression (None).
  • gzip, the standard levels of 1 through 9 are supported, where 1 is as fast as possible, with the least compression, and 9 is as compressed as possible, taking as much time as necessary.
  • lzjb -  is a fast method with tight compression ratios, which is standard with most Lempel-Ziv algorithms. LZJB seems to provide the best all around results in terms of performance and compression.
  • zle is a very fast compression method, with very light compression ratios.
  • lz4 - is intended as a faster and smarter replacement for lzjb
• Volume block size  - specifies the block size of the volume. The block size cannot be changed once the volume has been written, so it should be set at volume creation time. ​The default value is 128 KiB. 
  The value can be changed. You can choose between : 4; 8; 16; 32; 64; 128, 256; 512 [KiB] and 1 [MB].
• Write cache logging (sync) - you can choose from three options :
  • always (default)
  • standard
  • disabled
• ​Write cache logging (log bias) - Use this property to provide a hint to system about handling synchronous requests for a specific dataset. If logbias is set to Write log device (latency), ZX uses the pool's separate log devices, if any, to handle the requests at low latency. If logbias is set to In pool (throughput), the system does not use the pool's separate log devices. Instead, ZX optimizes synchronous operations for global pool throughput and efficient use of resources. The default value is Write log device (latency). For most configurations, the default value is recommended.

• Primary cache - Controls what is cached in the primary cache (ARC). If this property is set to "All", then both user data and metadata is cached. If this property is set to "None", then neither user data nor metadata is cached. If this property is set to "Metadata", then only metadata is cached. The default value is "All".
• ​Secondary cache - Controls what is cached in the secondary cache (L2ARC). If this property is set to "All", then both user data and metadata is cached. If this property is set to "None", then neither user data nor metadata is cached. If this property is set to "Metadata", then only metadata is cached. The default value is "All".

You can attach this newly created zvol to a target. To do that, you have to:

• choose one of the existing Target  names
• define the SCSI ID  for the target (you can generate a random SCSI ID number by clicking Generate button) 
• define the LUN for the target
• Access mode for the target - the default is Read-Write, You can choose the Read-Only option