Physical space chart
The Physical space chart shows the current usage of physical space in the entire storage cluster and on each particular tier. The used space includes the space occupied by all data chunks and their replicas, plus the space occupied by any other data.
How the physical space is calculated
The total physical disk space is a total of all the disk space on all storage disks on the same tier. The used physical space is a total of all the user data on the storage disks of the same tier, considering the redundancy mode. The free disk space is the total physical space minus the used physical space.
To better understand how physical disk space is calculated, consider the following example:
| Used/Total (Free), GiB | |||
|---|---|---|---|
|
Tier 0, 3+2 encoding (67% overhead) |
Tier 1, 2 replicas (100% overhead) |
Tier 2, no redundancy | |
| Node 1 | 334/1024 (690) | 134/512 (378) | 50/256 (206) |
| Node 2 | 334/1024 (690) | 133/512 (379) | 50/256 (206) |
| Node 3 | 334/1024 (690) | 133/512 (379) | |
| Node 4 | 334/1024 (690) | ||
| Node 5 | 334/1024 (690) | ||
| Reported summary | 1670/5120 (3450) | 400/1536 (1136) | 100/512 (412) |
The cluster has ten disks with the storage role: five 1024 GiB disks are assigned to tier 0, three 512 GiB disks to tier 1, and two 256 GiB disk to tier 2. There is no other data on the disks (for example, system files). Tier 0 stores 1000 GiB of user data in the 3+2 encoding mode. Tier 1 stores 200 GiB of user data in the 2 replicas mode. Tier 2 stores 100 GB of user data with no redundancy.
No matter what redundancy mode is used, the cluster attempts to spread data chunks evenly across disks of the same tier.
In this example, the physical disk space on each tier is reported as follows:
- On tier 0, the total disk space is 5120 GiB, the used disk space is 1670 GiB, and the free disk space is 3450 GiB.
- On tier 1, the total disk space is 1536 GiB, the used disk space is 400 GiB, and the free disk space is 1136 GiB.
- On tier 2, the total disk space is 512 GiB, the used disk space is 100 GiB, and the free disk space is 456 GiB.
See also