thanks for the reply. Yes, 4MB is the default. I have tried it. For example below (posted) is for 4MB (default) ran for 600 seconds. The seq read and rand read gives me a good bandwidth (not posted here). But with write its still very less. And I am particularly interested in block sizes. And rados bench tool has block size option which I have been using. Total time run: 601.106 Total writes made: 2966 Write size: 4194304 Object size: 4194304 Bandwidth (MB/sec): 19.7369 Stddev Bandwidth: 14.8408 Max bandwidth (MB/sec): 64 Min bandwidth (MB/sec): 0 Average IOPS: 4 Stddev IOPS: 3.67408 Max IOPS: 16 Min IOPS: 0 Average Latency(s): 3.24064 Stddev Latency(s): 2.75111 Max latency(s): 42.4551 Min latency(s): 0.167701 On Wed, Feb 10, 2021 at 9:46 AM Marc <Marc@f1-outsourcing.eu> wrote:
try 4MB that is the default not?
-----Original Message----- Sent: 10 February 2021 09:30 To: ceph-users <ceph-users@ceph.io>; dev <dev@ceph.io>; ceph-qa@ceph.io Subject: [ceph-users] struggling to achieve high bandwidth on Ceph dev cluster - HELP
Hi,
Hello I am using rados bench tool. Currently I am using this tool on the development cluster after running vstart.sh script. It is working fine and I am interested in benchmarking the cluster. However I am struggling to achieve a good bandwidth i.e. bandwidth (MB/sec). My target throughput is at least 50 MB/sec and more. But mostly I am achieving is around 15-20 MB/sec. So, very poor.
I am quite sure I am missing something. Either I have to change my cluster through vstart.sh script or I am not fully utilizing the rados bench tool. Or may be both. i.e. not the right cluster and also not using the rados bench tool correctly.
Some of the shell examples I have been using to build the cluster are bellow: MDS=0 RGW=1 ../src/vstart.sh -d -l -n --bluestore MDS=0 RGW=1 MON=1 OSD=4../src/vstart.sh -d -l -n --bluestore
While using rados bench tool I have been trying with different block sizes 4K, 8K, 16K, 32K, 64K, 128K, 256K, 512K. And I have also been changing the -t parameter in the shell to increase concurrent IOs.