[Linux-cluster] RE: Veritas Cluster Suite VS Redhat CLuster Suite

[Lin_ChiiShing at emc.com]

I am also interested to see any existing comparison between these two
clusters.

I am specifically interested in the performance of their cluster
mirrored volumes.
Here below is some performance test data I collected. (take it at your
own risk)

The VERITAS test configuration include two nodes cluster, a VG (Volume
Group) which consists of two physical disks,
and two LV (logical volumes) from this VG. One LV with cluster-striped
attributes, the other LV
with cluster-mirrored attributes. The IOMETER (sequential IO) IOPS data
follows:


IOsize			512B		4K		16K
32K  
 
Striped-read		20383		33845		12381
6226
Mirrored-read		22711		33934		11769
6080

Striped-write		10820		16711		8299
4817
Mirrored-write		9626		9283		4428
2600

The VERITAS test data looks as expected to me, for example, some
expected overhead for mirrored write,
and in general the IOPS number looks normal to me.

The RedHat cluster also include two nodes cluster. Two VGs, one VG is
local and the other VG with cluster property.
Each VG has three disks, and two LVs, the striped LV and the mirrored
LV. Its IOMETER (sequential IO) data follows:

IOsize				512B		4K		16K
32K  
 
Local-Striped-read		9070		7717		3795
3009
cluster-Striped-read		9180		7751		4686
3257
Local-mirrored-read		8724		7506		4922
3398
cluster-Mirrored-read		 331		 332		 332
332  <<<< why ?

Local-Striped-write		3711		3404		2626
1989
Local-Mirrored-write		 331		 331		 331
329  <<<  why ?
 

Does anyone know why the significant "read IO" performance degradation
on cluster-mirrored LV,
and the write IO drop on local-mirrored LV ? 

The RedHat component versions are:
	
[root at linux-cluster1 sbin]# ccs_tool  -V
ccs_tool DEVEL.1170370189 (built Feb 21 2007 15:11:13)
Copyright (C) Red Hat, Inc.  2004  All rights reserved.
[root at linux-cluster1 sbin]# cman_tool version
5.0.1 config 20
[root at linux-cluster1 sbin]# lvm version
    Logging initialised at Wed Apr 11 10:46:29 2007
    Set umask to 0077
  WARNING: Ignoring duplicate config node: library_dir (seeking
library_dir)
    Loaded external locking library liblvm2clusterlock.so
  LVM version:     2.02.18-cvs (2007-01-11)
  Library version: 1.02.14-cvs (2007-01-07)
  Driver version:  4.5.0
    Wiping internal VG cache

Is there a fix to the mirrored-LV performance in newer releases ?

    Thanks,
    -ChiiShing

-----Original Message-----
 
Date: Wed, 11 Apr 2007 09:24:48 +0200 (CEST)
From: laurent <laule75 at yahoo.fr>
Subject: [Linux-cluster] Veritas Cluster Suite VS Redhat CLuster Suite
To: linux-cluster at redhat.com
Message-ID: <182044.18633.qm at web26504.mail.ukl.yahoo.com>
Content-Type: text/plain; charset="iso-8859-1"

Hello,

I'm about to start an exhaustive study on the Veritas Cluster Suite and
the Redhat Cluster Suite  in order to compare their functionalities and
their performances The objective of this comparison is to determine our
future production Cluster environment.

As I don"t want to reinvent the wheel, are you aware  of any existing
study about this subject  ?

Any help would be greatly appreciated.

Kind regards

Laurent