Hi,
>From my observations, it depend of the action TSM is doing.
For example, when TSM is in initialisation state, there is a validation of all
the drives, in element addresses order.
When TSM is doing an audit libr checkl=y, it work the same
For that cases, and others, concerning ALL drives, TSM seems to act in element
adresses order
BUT when doing recurent task, as backup and so, TSM SEEMS to act as Richard
explain, asking the OS for a drive, so it's the OS which make the choice, based
on it own algorythm.
Larry, what are the reason why you want to know that point ?
Pierre
> -----Message d'origine-----
> De : ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] De
> la part de Kelly Lipp
> Envoyé : mercredi 22 août 2007 20:56
> À : ADSM-L AT VM.MARIST DOT EDU
> Objet : Re: [ADSM-L] How does a library choose a drive?
>
> I'm with Paul: TSM chooses the drive and based on my
> observations always does round robin. Not LRU as I don't
> think it keeps track of that. So it will choose the next
> drive in order as long at that drive isn't in use. If in
> use, skip to the next and keep going around.
>
> You see this on label libvol commands in particular.
>
>
> Kelly J. Lipp
> VP Manufacturing & CTO
> STORServer, Inc.
> 485-B Elkton Drive
> Colorado Springs, CO 80907
> 719-266-8777
> lipp AT storserver DOT com
>
> -----Original Message-----
> From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU]
> On Behalf Of Paul Zarnowski
> Sent: Wednesday, August 22, 2007 12:00 PM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: Re: [ADSM-L] How does a library choose a drive?
>
> Sorry to disagree, but I don't see how AIX can choose the
> drive - I believe that TSM chooses it. I don't know if it's
> LRU or round-robin, but I do know that it attempts to spread
> the load evenly.
>
> At 01:56 PM 8/22/2007, Mcnutt, Larry E. wrote:
> >Thanks Kelly, Richard and Andy for the quick responses. So, as I
> >understand it in my scenario, it is the AIX host that
> chooses the drive
>
> >that is the "least recently used" one. At the very
> beginning, it will
> >start at the first drive and sequentially go through them
> all and then
> >it will begin picking the "least recently used" drive to
> keep the usage
>
> >spread evenly across all the drives.
> >
> >-----Original Message-----
> >From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU]
> On Behalf
> >Of Andy Huebner
> >Sent: Wednesday, August 22, 2007 12:26 PM
> >To: ADSM-L AT VM.MARIST DOT EDU
> >Subject: Re: How does a library choose a drive?
> >
> >"Least Recently Used" I think is the management level explanation of
> >how it is done.
> >
> >Andy Huebner
> >
> >-----Original Message-----
> >From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU]
> On Behalf
> >Of Richard Sims
> >Sent: Wednesday, August 22, 2007 10:57 AM
> >To: ADSM-L AT VM.MARIST DOT EDU
> >Subject: Re: [ADSM-L] How does a library choose a drive?
> >
> >On Aug 22, 2007, at 11:32 AM, Mcnutt, Larry E. wrote:
> >
> > > TSM Server 5.3.3.0
> > > AIX 5.3
> > >
> > > This is probably not a TSM specific question, but
> hopefully someone
> > > can point me to the right place to look.
> > > We would like to understand how the library decides which
> available
> > > drive to use. ...
> >
> >It doesn't decide: the host determines which drive to use.
> >TSM uses them rotationally, to balance wear.
> >
> >For a 3494 library, see the MTIOCLM (Library Mount) library
> system call
>
> >in the IBM SCSI Device Drivers Programming Reference for the
> >nitty-gritty. For a SCSI library, where the host has to
> engage in more
>
> >intricate control of library mechanics, I believe it's the
> >SMCIOC_MOVE_MEDIUM call (Transport a cartridge from one element to
> >another element).
> >
> > Richard Sims
> >
> >
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> --
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> Manager, Storage Services Fx: 607-255-8521
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