[rescue] Looking for I/O performance metrics

[Chris Byrne]

Patrick,

Everything you said makes perfect sense, I just wish it were true ;-)

Here's the situation

The problem is occurring under light load or more precisely no essentially
no load.
It's only occurring on the Sun systems attached to the SAN not the windows
systems.
They are using Veritas to manage UFS filesystems on virtual mount points
created out of a single large LUN being presented to them from the SAN.

Yes I know that these are screwy

I've already recommended that they restructure their filesystems and put
their data on Oracle raw but I need to give them hard numbers on the current
upgefucked setup.

The system is basically set up as if it was on a JBOD array and they were
trying to reduce spindle contention, but with a large scale storage array
the array itself handles the contention and resource management issues so
anything you do on the filesystem side will just make things worse.


Chris Byrne


-----Original Message-----
From: rescue-admin at sunhelp.org [mailto:rescue-admin at sunhelp.org]On
Behalf Of Patrick Giagnocavo
Sent: 23 November 2001 17:05
To: rescue at sunhelp.org
Subject: Re: [rescue] Looking for I/O performance metrics


Chris Byrne wrote:
>
> All,
>
> I'm looking for some I/O measurement tools freely available for Solaris
2.6.
> I'm working on a SAN project at the moment and there's some weird stuff
> happening somewhere in the chain, and I need to isolate it. The sysadmin
is
> saying that it's the SAN, the SAN people are blaming the Solaris config
> etc... etc... and I'm stuck in the middle.

There are some freeware tools like the bonnie disk benchmark, iozone,
etc.

I will take a guess that you are not seeing this problem when your SAN
is lightly loaded, but under certain conditions when there is a higher
load.

You might want to run bonnie or iozone in the background while doing
some things in the foreground, or even run them on a seperate machine,
simply for the purposes of increasing the load on the SAN.

Am I right in guessing that your are using Oracle's raw partition
(instead of file-based) code on top of the SAN?

Cordially

Patrick Giagnocavo
patrick at zill.net
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