ADSM-L

Re: [ADSM-L] SV: Desperation, DR, and four TS3100 libraries...

2009-07-10 11:32:02
Subject: Re: [ADSM-L] SV: Desperation, DR, and four TS3100 libraries...
From: Wanda Prather <wprather AT JASI DOT COM>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Fri, 10 Jul 2009 11:30:30 -0400
Thanks Christian, and everyone, for the suggestions.

Even if I can convince TSM to work with the tapes spread across the 4
libraries, I think I still lose too much throughput.

If I want to restore multiple clients/filespaces in parallel, I think we
could easily get into the situation that client 1 is using the drive in
library 1, and the restore for client 2 needs a tape that is also in library
1.  The only way  I can see to keep all 4 drives busy is to use them in
manual mode.  (Short of doing MOVE NODEDATA to guarantee that every client
is on its own tape, which is highly unrealistic for a copy pool.  Not that
this scenario is realistic to begin with!)

Thanks everyone!
Wanda   (maybe another margarita will bring more enlightenment......)


On Fri, Jul 10, 2009 at 5:58 AM, Christian Svensson <
Christian.Svensson AT cristie DOT se> wrote:

> Hi Wanda,
> On my way to work this morning I have been thinking about your situation
> and I think I have an idea how you can get it to work. But only for restore
> not for backup... :)
> I haven't try this yet and probably don't have time to test it for you. But
> I think this will work.
>
> Define 4 SCSI Libraries
> Define 4 Drives. 1 to each Library
> Create 3 NEW Copypool Device Class that is pointing to Library 2,3 and 4
> (CopyClass2, CopyClass3, CopyClass4)
> And Update one Device Class to point to the 1st Library.
> Now do a Audit of the library with Owner=YOUR TSM SERVER
>
> In this stage does TSM know that ALL Tape are available but in different
> libraries.
>
> Technically it should work. The database knows what tape TSM need and only
> change the data entry-path for the tape in the same way it does with the
> "primary" (1st) Library you have.
>
> This is still just an crazy idea like always that I normally have.
>
>
> Best Regards
> Christian Svensson
>
> Cell: +46-70-325 1577
> E-mail: Christian.Svensson AT cristie DOT se
> Skype: cristie.christian.svensson
> ________________________________________
> Från: ADSM: Dist Stor Manager [ADSM-L AT VM.MARIST DOT EDU] f&#246;r Wanda
> Prather [wprather AT JASI DOT COM]
> Skickat: den 10 juli 2009 03:33
> Till: ADSM-L AT VM.MARIST DOT EDU
> Ämne: Desperation, DR, and four TS3100 libraries...
>
> I'm drawing a blank here, any suggestions welcomed.
>
> I have a TSM customer who makes their copypool tapes using a TS3200 with
> LTO4 drives.
> The TS3200 is a rack-mounted, 2 drive, 40-mumble slot standard ASCII
> library.  No issues.
> One copy pool, tapes vaulted and sent offsite.
>
> They want to go to a commercial DR vendor site and do a DR test next week.
> The commercial DR vendor, unbelievably, has no multi-drive LTO4-capable
> libraries.
>
> Instead, they want us to use 4 (count 'em, four) TS3100 libraries.
> The TS3100 is a rack-mounted, 1 drive, 20-mumble slot standard ASCII
> library.
>
> There's only 1 copy pool, so all tapes were created on the same device
> class.
> Ignoring the which-carts-would-go-in-which-library issue, I can't have a
> device class pointing to 4 libraries.
>
> And, the TS3100 is built in such a way that unlike a TS3500, you can't open
> the doors and access the drives for manual mounting.
> (I'd be happy to pull the covers off and try it, ignoring any warranties I
> might void, but I doubt the vendor will let me attack the thing with a
> screwdriver/wrench/hacksaw.)
>
> If I put all the carts in one TS3100 that will work, but that leaves me
> only
> 1 drive to restore all the clients, and they won't likely get done in the
> desired time window.
>
> The only thing I can think of to use all 4 drives, is to define those four
> TS3100's as 1 manual library with 4 manual drives, and use the front panel
> of each TS3100 to move tapes from the I/O slot to the drive when TSM
> requests a mount.
>
> (Actually the FIRST thing I thought of, was "cancel the DR contract, this
> is
> nonsense".  But my customer isn't convinced yet...)
>
> Anybody got a better solution?
> I've already tried a margarita, it didn't help....
>
> W
>