Hi Wanda -

What you found out is very interesting. Looks like you are getting decent
capacity on the 9840.We would like to improve our restore times by doing the
same conversion from DLT 7000 to 9840 that you now have in progress. I am
curious what you have seen in your environment as far as tape mount times
and time to data.

Thanks -
CR

__________________________________________________
Cris Robinson
Sr. Technical Analyst
Enterprise Storage Management / TSM (ADSM)
Liberty Mutual Insurance
Portsmouth, New Hampshire
603.431.8400.54837
mailto:cris.robinson AT libertymutual DOT com

        -----Original Message-----
        From:   Prather, Wanda [SMTP:Wanda.Prather AT JHUAPL DOT EDU]
        Sent:   Monday, February 14, 2000 12:49 PM
        To:     ADSM-L AT VM.MARIST DOT EDU
        Subject:        Re: ADSM 9840 & Compression

        We are running 9840's, converting all our old data from DLT7000.

        I'm getting exactly the same results on the 9840's that I saw on the
        DLT7000's.

        If I take a DLT7000 tape that filled at native capacity (35 GB),
then I know
        it was already-compressed data.  A MOVE DATA to a 9840 ends up
filling the
        9840 at 20 GB.

        If I take a DLT7000 that filled at 70-100GB, I know the data was not
        compressed to start with, and a MOVE DATA to a 9840 ends up filling
the 9840
        at 70-80GB.

        So it's working about as expected.  If the data is compressed by the
        software, it isn't going to compress much more in the hardware -
you'll get
        an additional 10% if you're lucky.

        Remember that even if you don't have COMPRESSION ON in the ADSM
client, some
        types of data are already naturally compressed - Windows machines
with
        stacking or compression on in the disk file system; Microsoft
Exchange
        files, SQL data base files, some types of graphics files such as
.tif and
        .gif files will compress little if at all.

        So I find the results on tape vary a whole lot.


************************************************************************
        Wanda Prather
        The Johns Hopkins Applied Physics Lab
        443-778-8769
        wanda_prather AT jhuapl DOT edu

        "Intelligence has much less practical application than you'd think"
-
        Scott Adams/Dilbert
        Scott Adams/Dilbert

************************************************************************





        > -----Original Message-----
        > From: Long, Matt [SMTP:Matt.Long AT MARRIOTT DOT COM]
        > Sent: Monday, February 14, 2000 9:45 AM
        > To:   ADSM-L AT VM.MARIST DOT EDU
        > Subject:      Re: ADSM 9840 & Compression
        >
        > John,
        >
        >         We are also seeing some bizzare compression rates with the
9840.
        > Some of our tapes are reporting over 80Gig of data. I don't know
if this
        > is
        > a bug or what. We are using ADSM attached to an AIX RS6000.
Thanks
        >
        > Matt Long
        > Systems Administration
        > Marriott International
        >
        >
        > -----Original Message-----
        > From: Doherty, John (ANFIS) [mailto:jdohe1 AT ANFIS.CO DOT UK]
        > Sent: Monday, February 14, 2000 5:46 AM
        > To: ADSM-L AT VM.MARIST DOT EDU
        > Subject: ADSM 9840 & Compression
        >
        >
        > ADSM ver 3 rel 1 level 2.20, device class defined as follows
        >
        >  <<...>>
        >
        > What level of the ADSM server are you running?
        >
        > Have you specified "9840C" as the format when configuring your
device
        > class?
        > (Q
        > DEVCLASS)
        >
        >
        > regards,
        >
        > Stuart Robertson
        > Unitech Open Systems Scotland
        >
        >
        > > John Doherty. Tel:   +44   (0)   141 275 7793
        > >               Fax:  +44   (0)   141 275 9199
        > >               Email: JDohe1 AT Anfis.co DOT uk
        > >
        > >       Technical Specialist, Storage Management L02S
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