Edit 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. Once created, the name can be changed as long as the zvol is NOT attached to a target, NOT used in a backup task and NO snapshots have been created yet.
• 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 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 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 provisioning - 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
  • 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 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 blocksize cannot be changed once the volume has been written, so it should be set at volume creation time. The default value is 128 KiB. You can choose between : 4; 8; 16; 32; 64; 128, 256; 512 [KiB] and 1 [MB].
• SYNC - you can choose between three options:
  • always (default)
  • standard
  • disabled
• ​LOG BIAS - Use this property to provide a hint to system about handling synchronous requests for a specific dataset. If logbias is set to latency, JovianDSS uses the pool's separate log devices, if any, to handle the requests at low latency. If logbias is set to throughput, the system does not use the pool's separate log devices. Instead, JovianDSS 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 - 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".
• ​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 newly-written data.

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

• choose one of the existing Target name
• define the SCSI ID for the target, you can generate a random SCSI ID number.
• define the LUN for the target
• Access mode for the target - the default is Read-Write, you can choose the Read-Only option.