[Gluster-devel] Changing the relative order of read-ahead and open-behind

Raghavendra Gowdappa rgowdapp at redhat.com
Fri Jul 21 07:26:09 UTC 2017

Hi all,

We've a bug [1], due to which read-ahead is completely disabled when the workload is read-only. One of the easy fix was to make read-ahead as an ancestor of open-behind in xlator graph (Currently its a descendant). A patch has been sent out by Rafi to do the same. As noted in one of the comments, one flip side of this solution is that small files (which are eligible to be cached by quick read) are cached twice - once each in read-ahead and quick-read - wasting up precious memory. However, there are no other simpler solutions for this issue. If you've concerns on the approach followed by [2] or have other suggestions please voice them out. Otherwise, I am planning to merge [2] for lack of better alternatives.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1084508
[2] https://review.gluster.org/#/c/15811/


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