ADSM-L

Re: 3390/Ramac cache and ADSM.

1999-12-20 15:07:50
Subject: Re: 3390/Ramac cache and ADSM.
From: "Bohnsack, JA James (6030)" <BohnsackJA AT GVL.ESYS DOT COM>
Date: Mon, 20 Dec 1999 14:07:50 -0600
Mark--I run a VM server, altho I don't think that the server platform will
make a difference.  My VMPRF output from last Friday, prime shift where all
the tape reclamation and data move processing takes place showed a very low
percentage of read activity to the DB Recovery areas.  Well less than 10%
read.  The DASD Storage pools, on the other hand showed read activity in the
70% range for some reason.  There were some backups going, altho not many
and some migration from disk to tape.  These numbers may be completely
different in the evening and night when the bulk of our backups are done,
but I don't collect the needed monitor output to know.

Depending on the cache characteristics of the RAMAC hardware, you may or may
not want to use cache.  For 3990/3390 dasd, I would be inclined to shut off
hardware caching for the DB and Recovery log.

Jim Bohnsack
Raytheon

> ----------
> From:         Mark Brown (CC Operations
> Supervisor)[SMTP:CCMB AT MUSICA.MCGILL DOT CA]
> Reply To:     ADSM: Dist Stor Manager
> Sent:         Thursday, December 16, 1999 6:34 AM
> To:   ADSM-L AT VM.MARIST DOT EDU
> Subject:      3390/Ramac cache and ADSM.
>
> ---------------------- Information from the mail header
> -----------------------
> Sender:       "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
> Poster:       "Mark Brown (CC Operations Supervisor)"
> <CCMB AT MUSICA.MCGILL DOT CA>
> Subject:      3390/Ramac cache and ADSM.
> --------------------------------------------------------------------------
> -----
>
> Hello,
>
> I've been trying to locate some info on IBM 3990 and IBM RAMAC dasd.
>
> I want to know if I should turn caching on or off when it comes to
> the following:
>
> ADSM Database Volumes
> ADSM Recovery Volumes
> ADSM Disk Storage Pools
>
> I'm talking about the cache in the IBM hardware, not the ADSM caching
> on disk pools.
>
> Thank You,
>   Mark Brown, Operations Supervisor
>   McGill University, Computing Centre
>   Phone (514) 398-2321
>   E-Mail --> ccmb AT musica.mcgill DOT ca
>   WWW Home Page --> http://mbrown.cc.mcgill.ca
>
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