[Gluster-users] gluster stripe

[Nick Birkett]

Some questions regarding the working of glusterfs striped over multiple 
servers (glusterfs 3.0.4)

(1)
I notice that when writing files I seem to get a file of (approximately) 
the same size on each file server: eg using /tmp (ext3)
filesystem on each of 8 servers:

comp00: -rw-r----- 1 sccomp users 4208066560 Jun 28 16:13 /tmp/BIG0
comp01: -rw-r----- 1 sccomp users 4208197632 Jun 28 16:13 /tmp/BIG0
comp02: -rw-r----- 1 sccomp users 4208328704 Jun 28 16:13 /tmp/BIG0
comp03: -rw-r----- 1 sccomp users 4208459776 Jun 28 16:13 /tmp/BIG0
comp04: -rw-r----- 1 sccomp users 4208590848 Jun 28 16:13 /tmp/BIG0
comp05: -rw-r----- 1 sccomp users 4208721920 Jun 28 16:13 /tmp/BIG0
comp06: -rw-r----- 1 sccomp users 4208852992 Jun 28 16:13 /tmp/BIG0
comp07: -rw-r----- 1 sccomp users 4208984064 Jun 28 16:13 /tmp/BIG0

This corresponds to an 4Gbyte file BIG0 on the glusterfs filesystem.

I was expecting 0.5Gbyte file on each server.

(2)
When running IOZONE benchmark with this setup I get a very poor write 
performance
( this would be expected if the file is being written to each server). 
The read performance is
as expected.

eg  115Mbyte/s write
      600Mbytes/s read.

I am wondering if my setup is faulty or this is expected.

Thanks,

Nick


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