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Set congestion-fill to approximately 90% of the size of sndbuf-size. If you are integrating a replication accelerator (DRX), set it to 90% of the DRX buffer. However, if the buffer is allocated a large size, say 10GB or more, the 90% threshold may be too large to detect congestion, so this should be adjusted to a reasonable value through tuning.
The recommended value for congestion-extents is 90% of the al-extents setting.
congestion-highwater detects congestion based on packet count. It is particularly appropriate for use in DR environments where capacity-based detection of replication congestion is not suitable. It is set to 20000 by default and is enabled by default. It is disabled when set to 0 and has a maximum value of 1000000.
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Transmission buffer (sndbuf) and DRX buffer It is difficult to allocate a large amount of the transmission buffer (sndbuf) set in bsr because it is allocated directly from kernel memory. This will vary depending on your system, but you will usually need to limit the size to within 1GB. Otherwise, if system kernel memory becomes insufficient due to transmission buffer allocation, system operation and performance may be affected. Therefore, if you need to configure a large buffer, it is recommended to configure it as a DRX buffer. |
Disk flush
If the target node suddenly goes down due to power failure during replication, data loss may occur if the disk cache area is not backed up by a battery backup device (BBWC). In order to prevent this in advance, in the process of writing data to the disk of the target, after data is written to the media, the flush operation is always performed to prevent data loss.
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