Hi,
               I have a situation where an apache web server is trying to 
locate the IndexDocument for a directory on a gluster volume.  This URL is 
being hit roughly 20 times per second.  There is only 1 file in this directory. 
 However, the parent directory does have a large number of items (+123,000 
files and dirs) and we are performing operations to move these files into 2 
levels of subdirs.

We are seeing very slow response times (around 8 seconds) in apache and also 
when trying to ls on this dir.  Before we started the migrations to move files 
on the large parent dir into 2 sub levels, we weren't aware of a problem.

[root@web-02 images]# time ls -l dir1/get/ | wc -l
2

real    0m8.114s
user    0m0.002s
sys     0m0.014s

Other directories with only 1 item return very quickly (<1 sec).

[root@Web-01 images]# time ls -l dir1/tmp1/ | wc -l
2

real    0m0.014s
user    0m0.003s
sys     0m0.006s

I'm just trying to understand what would slow down this operation so much.  Is 
it the high frequency of attempts to read the directory (apache hits to 
dir1/get/) ?  Do the move operations on items in the parent directory have any 
impact?

Some background info:

[root@web-02 images]# gluster --version
glusterfs 3.7.20 built on Jan 30 2017 15:39:29
Repository revision: git://git.gluster.com/glusterfs.git
Copyright (c) 2006-2011 Gluster Inc. <http://www.gluster.com>
GlusterFS comes with ABSOLUTELY NO WARRANTY.
You may redistribute copies of GlusterFS under the terms of the GNU General 
Public License.

[root@web-02 images]# gluster vol info

Volume Name: web_vol1
Type: Replicate
Volume ID: 0d63de20-c9c2-4931-b4a3-6aed5ae28057
Status: Started
Number of Bricks: 1 x 2 = 2
Transport-type: tcp
Bricks:
Brick1: web-01:/export/brick1/web_vol1_brick1
Brick2: web-02:/export/brick1/web_vol1_brick1
Options Reconfigured:
performance.readdir-ahead: on
performance.io-thread-count: 32
performance.cache-size: 512MB


Any insight would be gratefully received.

Thanks,
               Aaron

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