Hello Arun
No, it does not make a difference.
I had installed RedHat 8 on a local 240GB HP SSD.
I was told by our DBA that the command below should run for around 3 seconds and this is the result for a good filesystem speed. It is writing 18432 blocks of size of 16k
dd if=/dev/zero of=./test.out bs=16k count=18432 oflag=dsync
301989888 bytes (302 MB, 288 MiB) copied, 26.4979 s, 11.4 MB/s
On the MSA as you see I get more than 26 seconds which is far off.
What I can see is if I run multiple commands in parallel I get the same performance on each one of them which is the same as if I run one. So this will mean to me that something is limiting the performance on the storage for single tread access(for the lack of better description) and if I run it 4 times in parallel or a single every time the result is similar for all commands.
If I run the command to use big packets 16M and 144 of them I get
dd if=/dev/zero of=./test.out bs=16M count=144 oflag=dsync
2415919104 bytes (2.4 GB, 2.2 GiB) copied, 2.79892 s, 863 MB/s
So the bandwidth of the iSCSI is not a problem. To me, it looks like something is limiting the IOPS per single process.
If I run it against the root filesystem which is on the local SSD I get
dd if=/dev/zero of=./test.out bs=16k count=18432 oflag=dsync
301989888 bytes (302 MB, 288 MiB) copied, 2.98083 s, 101 MB/s
Which is what a good result should look like.
Do you know is there any logic on controllers the MSA2052 that limits the IOPS resources which a single host can utilize?