On Thu, May 4, 2017 at 4:36 PM, Xavier Hernandez <xhernan...@datalab.es> wrote:
> Hi, > > On 30/04/17 06:03, Raghavendra Gowdappa wrote: > >> All, >> >> Its a common perception that the resolution of a file having linkto file >> on the hashed-subvol requires two hops: >> >> 1. client to hashed-subvol. >> 2. client to the subvol where file actually resides. >> >> While it is true that a fresh lookup behaves this way, the other fact >> that get's ignored is that fresh lookups on files are almost always >> prevented by readdirplus. Since readdirplus picks the dentry from the >> subvolume where actual file (data-file) resides, the two hop cost is most >> likely never witnessed by the application. >> > > This is true for workloads that list directory contents before accessing > the files, but there are other use cases that directly access the file > without navigating through the file system. In this case fresh lookups are > needed. > I agree, if the contents of parent directory are not listed at least once, penalty is still there. > Xavi > > > >> A word of caution is that I've not done any testing to prove this >> observation :). >> >> regards, >> Raghavendra >> _______________________________________________ >> Gluster-devel mailing list >> Gluster-devel@gluster.org >> http://lists.gluster.org/mailman/listinfo/gluster-devel >> >> > _______________________________________________ > Gluster-devel mailing list > Gluster-devel@gluster.org > http://lists.gluster.org/mailman/listinfo/gluster-devel > -- Raghavendra G
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