CLI Guide

[-n|--name] name * Name for the new logging volume.
[-g|--geometry]
{raid-0|raid-1}
* Geometry for the new volume.
[-e|--extents]
context-path,context-
path...
* List of one or more storage-volume extents to use to create the logging volume. Must not be
empty, and must contain storage-volume extents that are all at the specified cluster. Entries must
be separated by commas.
Optional arguments
[-d|--stripe-
depth] depth
Required if --geometry is raid-0. Stripe depth must be:
● Greater than zero, but not greater than the number of blocks of the smallest element of the
RAID 0 device being created
● A multiple of 4 K bytes
A depth of 32 means 128 K (32 x 4 K) is written to the first disk, then the next 128 K is written to
the next disk.
Best practice regarding stripe depth is to follow the best practice of the underlying array.
Concatenated RAID devices are not striped.
* - argument is positional.
Description
Creates a logging volume. The new logging volume is immediately available for use with distributed-devices.
A logging volume is required on each cluster in metro node Metro configurations. Each logging volume must be large enough to
contain one bit for every page of distributed storage space (approximately 10 GB of logging volume space for every 160 TB of
distributed devices).
Logging volumes experience a large amount of I/O during and after link outages. Best practice is to stripe each logging volume
across many disks for speed, and to have a mirror on another fast disk.
To create a logging volume, first claim the storage volumes that will be used, and create extents from those volumes.
● Use the ll /clusters/cluster/storage-elements/storage-volumes command to display the available storage
volumes on the cluster.
● Use the storage-volume claim -n storage-volume_name command to claim one or more storage volumes.
● Use the extent create -d storage-volume_name, storage-volume_name command to create an extent to use for the
logging volume.
Repeat this step for each extent to be used for the logging volume.
Table 12. logging volume display fields
Field Description
application-consistent
Whether or not this storage volume is application-consistent.
biggest-free-segment-block-count
The block count of the largest remaining free segment in the
logging volume. This is the upper limit on the size of a new
allocated segment.
block-count
The number of blocks in the volume.
block size
The size of a single block, in kilobytes.
capacity
The total number of bytes in the volume. Equals the block-
size multiplied by the block-count.
component-count
The number of mirrors in this raid-1 logging volume.
free-capacity
The number of free slots for storage-volume headers in this
logging volume.
Commands 221