Ben England
2014-Aug-12 12:48 UTC
[Gluster-users] Gluster-users Digest, Vol 76, Issue 18 - Re: reading not distributed across bricks
> Message: 1 > Date: Mon, 11 Aug 2014 09:53:30 -0400 (EDT) > From: Justin Clift <justin at gluster.org> > To: Pranith Kumar Karampuri <pkarampu at redhat.com> > Cc: gluster-users at gluster.org, Ray Mannings <manningsray1 at gmail.com> > Subject: Re: [Gluster-users] Reading not distributed across bricks > Message-ID: > <417182971.4749068.1407765210056.JavaMail.zimbra at redhat.com> > Content-Type: text/plain; charset=utf-8 > > ----- Original Message ----- > > hi Ray, > > Reads are served from the bricks which respond the fastest at the > > moment. They are not load-balanced. > > Maybe a good feature for 3.7? :) >Ray, There already is a feature, from gluster volume set help: "Option: cluster.read-hash-mode Description: inode-read fops happen only on one of the bricks in replicate. AFR will prefer the one computed using the method specified using this option 0 = first responder, 1 = hash by GFID of file (all clients use same subvolume), 2 = hash by GFID of file and client PID" This is particularly useful for benchmark tests, where the system may not have response time data sufficient to properly load balance and I have seen all the clients select the same replica using default value of 0. The value 2 is nice because if many clients are reading the same file, the load is distributed across bricks. -ben