Question about bsize parameter

[Ceva]

Good day,
I would like to clarify parameter bsize in mqldt utility.
Is it hdd/sdd block size which we can set during fs creation (like mkfs.ext4 -b 16384)?

[stmassey]

Hi,
The block size parameter is a value (or comma seperated list of values) that indicate the block size when writing to the indicated device. This is the 'chunk' or amount of data that is written by each writev call.

Different IO systems will performance will vary with block size as its generally more efficient to write in larger chunks. MQ will vary its block size dependent on message size, workload and performance of the underlying IO system.

You can see the average write size a particular QM is using when using the amqsrua utlity to introspect a running QM.