SUMMARY:Performance of concatenated disks using DiskSuite 4.2

From: Deepak Sinha (
Date: Thu Jan 28 1999 - 13:34:26 CST

First of all I extend my appriciation to following people who replied to
my posting:

Brooke King <>
David Evans <>
Kevin Sheehan - Uniq <>
Jeff Woolsey <>
Nick Czeczulin <>

Perhaps I was not clear in my posting that my requirement was to have ONE
big filesystem of 26 MB with minimum amount of performance degradation.

I liked the idea of striping the two 9 GB disks together, striping the 4GB
disk and 4 GB partition, and then concatenating the two stripes together
for a total of 26GB filesystem.
This will certainly give better performance than my idea of concatenating
all four of them.

Once again thanks,

Deepak Sinha
Deepak K. Sinha Voice: (847)467-2457 (W)
Technical Services Specialist Fax# : (847)467-3280 (W)
1890 Maple Avenue. Room 202 Home#: (847)733-9879 (H)
ILS,Northwestern University,Evanston,IL 60201 Email:

Original Posting:

Date: Wed, 27 Jan 1999 14:35:39 -0600 (CST)
From: Deepak Sinha <>
Subject: Performance of concatenated disks using DiskSuite 4.2
I have an Ultra-10 running Solaris-7 with 128MB of RAM. I have an internal
8.5 GB IDE drive and an external UltraScsi-Multipack with two 9GB hard
disks and one 4 GB hard disk.
Internal disk has a 4GB unused partition ( c0t0d0s6 ), disks in the
multipack are all unused and I have partitioned and labeled them such
that 0th partition on each disk (c1t1d0s0 (9GB), c1t2d0s0 (9GB),
c1t3d0s0(4GB)) contains the entire space.
I am planning to concatenate the two 9GB disks ( identical disk geometry),
the 4GB disk (disk geometry different from all other drives), and the 4GB
unused partition on the internal disk (disk geometry different from all
other drive) as a metadevice and create one 26GB (approx.) filesystem on
it using Solstice DiskDuite 4.2.
I have read ducumentation on which suggests that for
concatenation or striping, disk geometry of all the disks should be same,
otherwise there will be a performance degradation.
My question is related to the degree of performance degradation, i.e. what
kind of performance loss I am expecting? Afterall, if loss in performance
is reasonable then I don't have to buy addtional disks
The system in question will be a News server and very moderately used,
will receive about 1GB of news feed spread over a 24 hour period.
I will look forward to your comments and will summerize,
Deepak Sinha

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