From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Marzinski Date: Fri, 15 Apr 2016 11:33:43 -0500 Subject: [Cluster-devel] [PATCH] gfs2(5): add rgrplbv and loccookie info the the manpage Message-ID: <1460738023-7874-1-git-send-email-bmarzins@redhat.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit The gfs2 man page didn't have any information about the rgrplvb and loccookie mount options. This patch adds it. Signed-off-by: Benjamin Marzinski --- gfs2/man/gfs2.5 | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/gfs2/man/gfs2.5 b/gfs2/man/gfs2.5 index 0517944..56d1a00 100644 --- a/gfs2/man/gfs2.5 +++ b/gfs2/man/gfs2.5 @@ -165,6 +165,40 @@ the statfs information on a local basis before it is synced back to the master statfs file, even if the time period has not expired. If the setting of statfs_quantum is 0, then this setting is ignored. +.TP +\fBrgrplvb\fP +This flag tells gfs2 to look for information about a resource group's free +space and unlinked inodes in its glock lock value block. This keeps gfs2 from +having to read in the resource group data from disk, speeding up allocations in +some cases. This option was added in the 3.6 Linux kernel. Prior to this +kernel, no information was saved to the resource group lvb. \fBNote:\fP To +safely turn on this option, all nodes mounting the filesystem must be running +at least a 3.6 Linux kernel. If any nodes had previously mounted the filesystem +using older kernels, the filesystem must be unmounted on all nodes before it +can be mounted with this option enabled. This option does not need to be +enabled on all nodes using a filesystem. +.TP +\fBloccookie\fP +This flag tells gfs2 to use location based readdir cookies, instead of its +usual filename hash readdir cookies. The filename hash cookies are not +guaranteed to be unique, and as the number of files in a directory increases, +so does the likelihood of a collision. NFS requires readdir cookies to be +unique, which can cause problems with very large directories (over 100,000 +files). With this flag set, gfs2 will try to give out location based cookies. +Since the cookie is 31 bits, gfs2 will eventually run out of unique cookies, +and will fail back to using hash cookies. The maximum number of files that +could have unique location cookies assuming perfectly even hashing and names of +8 or fewer characters is 1,073,741,824. An average directory should be able to +give out well over half a billion location based cookies. This option was added +in the 4.5 Linux kernel. Prior to this kernel, gfs2 did not add directory +entries in a way that allowed it to use location based readdir cookies. +\fBNote:\fP To safely turn on this option, all nodes mounting the filesystem +must be running at least a 4.5 Linux kernel. If this option is only enabled on +some of the nodes mounting a filesystem, the cookies returned by nodes using +this option will not be valid on nodes that are not using this option, and vice +versa. Finally, when first enabling this option on a filesystem that had been +previously mounted without it, you must make sure that there are no outstanding +cookies being cached by other software, such as NFS. .SH BUGS -- 2.1.0