ADSM-L

Re: LTO strange behaviour

2002-02-12 10:38:46
Subject: Re: LTO strange behaviour
From: "Kauffman, Tom" <KauffmanT AT NIBCO DOT COM>
Date: Tue, 12 Feb 2002 10:18:46 -0500
Richard --

We run our TSM server on a system that serves as our SAP fallover box, and
I've more experience than I'd like with both services running on the same
physical system. What I had at the time (about now, last year) was a TSM
server that would do 9 MB/sec to each of 5 DLT drives (45 MB/sec total
throughput) when the two systems were seperate -- and just over 6 MB/sec per
drive (30 MB/sec total) when SAP and TSM were on the same box. I never got
into serious debug, but it looks like a lot of the TCP/IP tuning doesn't
seem to apply to the local loopback interface.

Also, if you think about it -- with two boxes, you've got backint reading
local disk and writing to the network on box A and TSM reading the network
and writing to tape on box B. With one box, backint is reading disk and
writing to local loopback; TSM is reading local loopback and writing to
tape. You've really got twice the I/O running.

Tom Kauffman
NIBCO, Inc

> -----Original Message-----
> From: Denzel, Richard van [mailto:Richard.vanDenzel AT GETRONICS DOT COM]
> Sent: Monday, February 11, 2002 3:33 AM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: Re: LTO strange behaviour
>
>
> James,
>
> The backup is made from the TDP for R/3 running on the same
> system as TSM.
> The backup is around 100 GB. The backup is indeed from the
> local storage
> (SSA in mirror).
>
> We've already tried the settings on the server side. When we
> try to set TXNB
> on the client side, the backup from TDP for R/3 crashes.
> I've also tried using SHMEM instead of TCPIP, but TDP for R/3 doesn't
> support that, because of the TSM is running as root and TDP has to be
> running as ora<SID>.
>
> We're at the latest microcode and we've also dropped the
> problem with Tivoli
> Support and it's still in the labs there somewhere.
>
> Richard.
>
> -----Original Message-----
> From: James Thompson [mailto:mezron AT HOTMAIL DOT COM]
> Sent: Friday, February 08, 2002 3:46 PM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: Re: LTO strange behaviour
>
>
> What you really need to find out is how fast are you sending
> data to the LTO
> tape drives.  The tape drives can only go as fast as the data
> stream you
> send to them.  Or as fast as the destination can accept on a
> restore.  If
> you are only sending 2.5 MB/sec to the tape drives, then
> don't complain when
> the tape drives run at 2.5 MB/sec.
>
> You state that you are doing a backup.  What size and how
> many files are you
> sending.  If this is a LAN backup, how much bandwidth does
> your TSM server's
> network have?  If this is a backup from the TSM server's
> local storage, what
> type is it?
>
> If you have lots of small files, or your are bandwidth
> limited because of
> your network.  You should send the backup to disk storage,
> then migrate off
> to tape.
>
> Check the following settings and try setting them to these values.
>
> TSM Server:
>
> TXNGroupmax 256
> MOVESizethresh 500
> MOVEBatchsize 1000
>
> TSM Client:
>
> TXNBytelimit 2097152
>
> Also upgrade to the latest level of microcode.  And if all
> else fails,  open
> a support call with IBM and have them assist you.
>
> James Thompson
>
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