I noticed recently that SMB read speeds with 6.7.x from the shares went way down from approx 100mb/s to 20-30mb/s. After investigation it turned out that when transfering from the disk shares directly intead of going through through the normal shares (spanning several disks) restored the normal speed. Before i realized this i tried a lot of options without any luck (network offloading, flow control, buffer sizes, maxprotocol, tunables, etc).
But then i tried to turn direct i/o OFF. And that did the trick, normal speeds are restored. This is ironic as in pre 6.x.x times I had to turn direct i/o ON to get normal speeds when copying internally (with mc) between drives (unassinged devices) and the fused shares. It seems that some of the recent changes (maybe the new buffering in the fused filesystem) interact badly with direct i/o. I did not test if internal transfer speeds are affected by turning direct i/o off in 6.7.x, as i rarely do that nowadays.
But if anybody experiences such issues, turning OFF direct i/o might be worth a try.
Recommended Comments
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.