[Gluster-users] Arbiter performance issue

[Russell Purinton]

Hi all, sorry for 2 threads today, but I felt like this deserved a separate thread…

I was trying to replace my replica 2 volumes with replica 3 arbiter 1 volumes…  The new volumes though are 10x slower on direct writes than their replica 2 counterparts.  Im wondering if this is to be expected or if I might have done something wrong?   I confirmed that no data is being written into the arbiter bricks, just meta data.



   Here’s the tests I ran.   I did the dd tests multiple times with different file names, and they all had the same speeds ….

[root at fs134 wtg002]# dd if=/dev/zero of=test bs=1M count=100 oflag=direct
100+0 records in
100+0 records out
104857600 bytes (105 MB) copied, 9.49974 s, 11.0 MB/s
[root at fs134 wtg002]# cd ..
[root at fs134 home]# cd wtg001
[root at fs134 wtg001]# dd if=/dev/zero of=test bs=1M count=100 oflag=direct
100+0 records in
100+0 records out
104857600 bytes (105 MB) copied, 0.888929 s, 118 MB/s
[root at fs134 wtg001]# gluster volume info wtg001

Volume Name: wtg001
Type: Distributed-Replicate
Volume ID: 53179cfe-9896-4c94-9f1d-01dd474e027e
Status: Started
Number of Bricks: 2 x 2 = 4
Transport-type: tcp
Bricks:
Brick1: xs141:/brick1/wtg001p0r0
Brick2: xs138:/brick1/wtg001p0r1
Brick3: xs139:/brick1/wtg001p1r0
Brick4: xs140:/brick1/wtg001p1r1
Options Reconfigured:
nfs.disable: on
performance.readdir-ahead: on
[root at fs134 wtg001]# gluster volume info wtg002

Volume Name: wtg002
Type: Distributed-Replicate
Volume ID: 410b67ad-bc1e-473b-b98f-ad431d7c9831
Status: Started
Number of Bricks: 2 x 3 = 6
Transport-type: tcp
Bricks:
Brick1: xs141:/brick1/wtg001d2r0
Brick2: xs138:/brick1/wtg001d2r1
Brick3: xs139:/brick1/wtg001d2ra
Brick4: xs139:/brick1/wtg001d3r0
Brick5: xs140:/brick1/wtg001d3r1
Brick6: xs141:/brick1/wtg001d3ra
Options Reconfigured:
nfs.disable: on
performance.readdir-ahead: on
[root at fs134 wtg001]# mount | grep wtg
0:/wtg001 on /home/wtg001 type fuse.glusterfs (rw,default_permissions,allow_other,max_read=131072)
0:/wtg002 on /home/wtg002 type fuse.glusterfs (rw,default_permissions,allow_other,max_read=131072)
[root at fs134 wtg001]#


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