Storage QPI¶
The storage QPI gives user an overall score for storage performance.
The measurement is done by StorPerf.
System Information¶
System Information are environmental parameters and factors may affect storage performance:
| System Factors | Detail | Extraction Method |
| Ceph Node List | List of nodes which has ceph-osd roles. For example [node-2, node-3, node-4]. | Getting from return result of installer node list CLI command. |
| Ceph Client RDB Cache Mode | Values: “None”, “write-through”, “write-back”. | Getting from value of “rbd cache” and “rbd cache max dirty” keys in client section of ceph configuration; To enable write-through mode, set rbd cache max dirty to 0. |
| Ceph Client RDB Cache Size | The RBD cache size in bytes. Default is 32 MiB. | Getting from value of “rdb cache size” key in client section of ceph configuration. |
| Ceph OSD Tier Cache Mode | Values: “None”, “Write-back”, “Readonly”. | Getting from ceph CLI “ceph report” output info. |
| Use SSD Backed OSD Cache | Values: “Yes”, “No”. | Getting from POD description and CEPH CLI “ceph-disk list” output info. |
| Use SSD For Journal | Values: “Yes”, “No”. | Getting from POD description and CEPH CLI “ceph-disk list” output info. |
| Ceph Cluster Network Bandwidth | Values: “1G”, “10G”, “40G”. | Getting from physical interface information in POD description, “ifconfig” output info on ceph osd node, and value of “cluster network” key in global section of ceph configuration. |
Test Condition¶
| Test Condition | Detail | Extraction Method |
| Number of Testing VMs | Number of VMs which are created, during running Storperf test case. | It equals the number of Cinder nodes of the SUT. |
| Distribution of Testing VMS | Number of VMs on each computer node, for example [(node-2: 1), (node-3: 2))]. | Recording the distribution when runing Storperf test case. |
Baseline¶
Baseline is established by testing with a set of work loads:
- Queue depth (1, 2, 8)
- Block size (2KB, 8KB, 16KB)
- Read write - sequential read - sequential write - random read - random write - random mixed read write 70/30
Metrics¶
- Throughput: data transfer rate
- IOPS: I/O operations per second
- Latency: response time
Workload Scores¶
For each test run, if an equivalent work load in baseline is available, a score will be calculated by comparing the result to baseline.
Section Scores¶
| Section | Detail | Indication |
|---|---|---|
| IOPS | Read write I/O Operation per second under steady state Workloads : random read/write | Important for frequent storage access such as event sinks |
| Throughput | Read write data transfer rate under steady state Workloads: sequential read/write, block size 16KB | Important for high throughput services such as video server |
| Latency | Average response latency under steady state Workloads: all | Important for real time applications |
Section score is the geometric mean of all workload score.
Storage QPI¶
Storage QPI is the weighted arithmetic mean of all section scores.