Hi, I have a requirement to completely disable gluster caching and measure performance on PCIe SSD drive. Below is my vol configuration for disabling performance. With these settings, I still see raw SSD speed doesn't match with the numbers shown by fio with gfapi engine i.,e fio shows speed of 1.5GB/s but raw speed measured at SSD using iostat is around 250-300MB/s, not sure where the rest is coming from. My assumption was if gluster caching is completely disabled, fio speed should be very close to raw SSD speed. Can anyone please guide me in understanding the same? [root at vsan-blr4 prashanth]# gluster vol info Volume Name: fvol_tun Type: Distribute Volume ID: 0beec43e-7f75-40e6-8153-075cbd7c3fc8 Status: Started Number of Bricks: 2 Transport-type: rdma Bricks: Brick1: 192.168.1.3:/fdata/fbrick1/fvol_tun Brick2: 192.168.1.4:/fdata/fbrick1/fvol_tun Options Reconfigured: performance.cache-size: 32MB performance.write-behind-window-size: 524288 performance.flush-behind: off performance.write-behind: off performance.io-cache: off diagnostics.count-fop-hits: on diagnostics.latency-measurement: on performance.readdir-ahead: on server.allow-insecure: on auth.allow: 192.168.1.* performance.io-thread-count: 32 diagnostics.brick-log-level: TRACE diagnostics.client-log-level: TRACE debug.trace: write-behind debug.log-file: yes debug.include-ops: yes performance.strict-o-direct: on -Prashanth HGST E-mail Confidentiality Notice & Disclaimer: This e-mail and any files transmitted with it may contain confidential or legally privileged information of HGST and are intended solely for the use of the individual or entity to which they are addressed. If you are not the intended recipient, any disclosure, copying, distribution or any action taken or omitted to be taken in reliance on it, is prohibited. If you have received this e-mail in error, please notify the sender immediately and delete the e-mail in its entirety from your system. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://www.gluster.org/pipermail/gluster-users/attachments/20160104/fcc6331d/attachment.html>