Add new zvol

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

• NAME - Name the new Zvol
• SIZE - Size of new Zvol. The unit for this values is GiB (Gibibyte).

​In general, if You multiply 1024 ·1024 ·1024 = 1 073 741 824b, which is a result of eqaul 2^30.

For example, 1 GiB = 1024 × 1 MiB = 1024 × 1024 × 1 KiB = 1024 × 1024 × 1024 × 1 B = 1 073 741 824 ~ 1070 GB

• PROVISIONING :
  • ​thin provisioning - 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 provisionning - 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, but is zeroed out.

• DEDUPLICATION :
  • ​Disbaled (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
  • sha 256 - performs a operation where 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.
  • sha 256, verify - enables an ability to detect and correct hash collisions, however this is very system intensive and is not recommended for casual use

• COMPRESSION - there are several data compression methods - You will see all available methods from the drop-down list. The default compression method is LZ4.You can also choose no compression (NONE).
  • GZIP, the standards 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 it 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  - the default value is 64 KiB. The value can be changed. You can choose between : 0,5 ; 1; 2; 4; 8; 16; 32; 64; 128 [KiB].

• SYNC  - you can choose between three options :
  • always (default)
  • standard
  • disabled
• ​LOG BIAS - allows to setup between the latency (default) and throughput.
  • ​You can use this property to provide a hint to ZFS about handling synchronous requests for a specific dataset. Iflogbias is set to latency, ZFS uses the pool's separate log devices, if any, to handle the requests at low latency. If logbias is set to throughput, ZFS does not use the pool's separate log devices. Instead, ZFS optimizes synchronous operations for global pool throughput and efficient use of resources. The default value is latency. For most configurations, the default value is recommended. 
• PRIMARY CACHE - one of three options have to be chosen :
  • all (default)
  • none
  • metadata
• ​SECONDARY CACHE - one of three options have to be chosen :
  • all (default)
  • none
  • metadata
• ​COPIES - number of copies of the data.  As a default, it is set to 1.