ADSM-L

Re: tape storage vs. disk storage

1997-04-01 09:32:46
Subject: Re: tape storage vs. disk storage
From: Mark Rizzo <RizzoM AT MAIL.DEC DOT COM>
Date: Tue, 1 Apr 1997 09:32:46 -0500
Ron,

Did you say "counter-intuitive"? Well that's exactly how we felt until
we
got our hands on a document titled, ADSTAR Distributed Storage Manager
Version 2 Release 1.5 Performance Evaluation Report. This report
reinforced
our findings exactly (pages 43-44). I/O rate increased 3X - 4X when
writing directly
to the 3590 tape drive. IBM reports this is no mystery or illusion,
3590's stream
the data where disks can't. Go figure.

Mark RIzzo
DOD
rizzom AT mail.dec DOT com

PS. No migration involved.

>----------
>From:  Clendenny, Ronald D.[SMTP:rdclendenny AT CAL.UE DOT COM]
>Sent:  Monday, March 31, 1997 4:34 AM
>To:    ADSM-L AT VM.MARIST DOT EDU
>Subject:       Re: tape storage vs. disk storage
>
>Now why would there be an increase in the data transfer rate going
>direct to tape?  That seems counter-intuitive.  Was migration competing
>with the backup?
>
>Ron Clendenny  <rdclendenny AT cal.ue DOT com>
>Callaway Nuclear Power Plant
>Fulton, Missouri
>
>"The difference between a madman and me is that I am not mad" - Salvador
>Dali
>
>>-----Original Message-----
>>From:  Mark Rizzo [SMTP:RizzoM AT MAIL.DEC DOT COM]
>>Sent:  Thursday, March 27, 1997 1:04 PM
>>To:    ADSM-L AT VM.MARIST DOT EDU
>>Subject:       Re: tape storage vs. disk storage
>>
>>Michael,
>>
>>You can go directly to your tape drive but you must realize, your
>>backups/archives will backup (queue) if you don't have enough tape
>>drives.
>>While a disk backup pool can handle many backups at once, a direct
>>to tape backup must wait it's turn. One thing we did discover regarding
>>direct to tape backup, was a tremendous increase in data transfer rate.
>>Going to our disk pool we averaged 700kb/sec. But when we directed the
>>data to our tape pool, we got 3Mb/sec..(3590 tape drives)
>>
>>Mark Rizzo
>>DoD
>>
>>
>>>> From:         Michael Castillo[SMTP:mcastill AT UTEP DOT EDU]
>>>> Sent:         Tuesday, March 25, 1997 11:37 AM
>>>> To:   ADSM-L AT VM.MARIST DOT EDU
>>>> Subject:      tape storage vs. disk storage
>>>>
>>>>         Does anyone out there just dump to tape only and not store
>>>> data on
>>>> disk(ex.3390,3380)? Can this be done?
>>>>
>>>>
>>>>
>>>> Michael A.Castillo
>>>> Software Systems Specialist
>>>> Ph:747-5256
>>>> Fax:747-5067
>>>> Beeper :546-3756
>>>> E-Mail: mcastill AT utep DOT edu
>>>>
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>>>
>
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