HSZ70 and target ID assignments for optimal I/O

From: Michael Grau <Michael.Grau_at_alphawest.com.au>
Date: Mon, 14 Dec 1998 08:36:30 +0800

This should be a simple question to answer.

We have an alpha 4100 server running digital UNIX with raid cabinets
connected via hsz70 controllers. When this was originally setup the
procedure was to install disks using sequential numbers for target scsi ids.
That is, as each disk was added a new LUN was generated until moving to the
next sequential scsi target id as follows: D104, D105, D106, D200, D201 etc.

Will there be significant gains in moving disks to different scsi targets?
These disks are typically 9 GB running Oracle across multiple disks. They
are not striped but each Oracle database may straddle a number of disks, as
these have been installed sequentially the same Oracle Instance is likely to
straddle a number of disks all with the same target id. In this way I would
think it beneficial to move them to different target IDs but I am unsure if
there will be any gains. Can anyone tell me the relationship between scsi
targets in this setup? Is this just a token assignment by the HSZ70
controller or does it have I/O impact as on other systems?

I will summarise.







Michael Grau
Network Engineer

Enterprise Managed Services
AlphaWest Pty Ltd
Ph: (08) 9237 3041
Mobile: 041 331 5820
email: michael.grau_at_alphawest.com.au
visit our website : http://www.alphawest.com.au
Received on Mon Dec 14 1998 - 00:39:19 NZDT

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