[Gluster-users] drop in write performance

Ason Hu tobechihiro at gmail.com
Mon Feb 2 09:12:25 UTC 2015


In my small file test, 3 types of volume are created in same GlusterFS
Cluster (4 nodes)

   - Distritubed
   - Distributed Replicated
   - Distributed Striped

10 million small files (8 byte) create and search each test cycle life

Nodes info :

   - OS : CentOS 6.6 64bit
   - RAM : 64GB
   - HDD : 4TB, 7200RPM, SAS *6 RAID 0
   - FileSystem : XFS, BS=4K

Problem :

It occur when file reach ≒200 million (sum of 3 volumes)
files created speed drop from  ≒1500 to  ≒100

Though the speed of creation become slow but search speed and throughput
still good
Seems each types of volume have same problem, I don't know what cause this

Workaround :

I try to create new volume ( Distributed | Distributed Replicated |
Distributed Striped ), mount it,
problem solved!
But the old volume write speed still sad..

I'd  try to increase below volume setting, but don't work at all

   - performance.cache-size
   - performance.io-thread-count

I didn't enable the volume qouta option.
Does glusterfs volume have some kind of limitation of file creation?

Nosa Hu,
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