Recommendations for setting up primary memory and cache

  • Primary memory

    • Create a partition for each HD store

    • The drive should only be written by the ibaHD-Server

    • Do not use the HD partition(s) as memory for .dat files or other purposes

  • Cache

    • Use an SSD disk with a balanced ratio of read and write performance

    • You can use the SSD disk as an intermediate storage for several HD stores, depending on the data throughput of the HD stores

    • Depending on the performance class and generation of the used SSD, availability and performance may decrease over the operating time. A method of ensuring the performance of the SSD for longer is to leave up to 20% of the SSD disk unpartitioned. If you have any questions, please contact iba support.

    • SSD hard disk with NVMe interface is advantageous

Size of the intermediate store

The size of the buffer used depends on the number of signals, regardless of whether they are analog or digital signals. The signals are saved in segment files. At least one segment file exists in the ibaHD-Server for each aggregation level.

ibaHD-Server has a limit regarding the size of the segment file and also the number of signals per segment file. The number of signals per segment file depends on the aggregation level.

Maximum segment file size: 512 MB

Maximum number of signals per segment per aggregation level:

Level 0 (raw)

256

Level 1

512

Level 2

1024

Level 3

2048

Level 4

4096

Level 5

8192

The number of configured signals determines the number of segment files per level and the size of the store.

Example:

Signal count total 5000, segment size max. 512 MB

Max. signal count/seg

#Segments

Max. size

Segments Count L0

256

20

10240

Segments Count L1

512

10

5120

Segments Count L2

1024

5

2560

Segments Count L3

2048

3

1536

Segments Count L4

4096

2

1024

Segments Count L5

8192

1

512

Store size

20992 MB

Store size opt. configured (3* Level0)

30720 MB

At the time of configuration, the size of the intermediate storage used cannot be determined due to the unknown number of data to be stored, but also because the number of signals can change again and again due to reconfiguration in ibaPDA. Therefore, ibaHD-Server expects the minimum size described in chapter Configure HD stores.

If the intermediate storage is smaller than the calculated memory size to be used, ibaHD-Server internally reduces the size of the segment files so that all Level 0 segment files only occupy 1/3 of the intermediate storage. This leads to more file transfers between intermediate and main storage.

Therefore, after adding signals in ibaHD-Server, the configuration of the intermediate storage should be compared with the required space.