ADSM-L

Re: SAP-Backint-ADSM

1999-11-04 10:28:05
Subject: Re: SAP-Backint-ADSM
From: "Kauffman, Tom" <KauffmanT AT NIBCO DOT COM>
Date: Thu, 4 Nov 1999 10:28:05 -0500
Ralf, I had the same experience - except that I never got over 84 GB/hour on
the backup. The SAP DB server was an 8-way 604e high node and the ADSM
server was a 4-way 604e high node. My experience was that the disk subsystem
was the bottleneck on the restore. I'd see 13 or 14 MB/sec through the
switch for 30 to 50 seconds, with little disk activity, and then the drives
would go 100% busy for 8 to 20 seconds and the throughput on the switch
would drop to 1.5 to 6 MB/sec.

We migrated to S7A servers for both ADSM and SAP in September, using two
Gigabit ethernet adapters to replace the switch. With the same 4.5 GB SSA
drives (about 280 of them) I now get 140 to 160 GB/hour on the backup. I
don't have a restore time for this environment -- but we moved our test
instance to an H50 (4-way) and restore at 40 GB/hour over dual 100 Mb
ethernet; previously this was an 8-way 604 high node that restored at 26
GB/hour over the SP switch.

I use Jussi Maki/Marcel Mol's "monitor for AIX" for real-time monitoring.
I'm also configured for run-length compression in backint (average
compression 1.28) using 4 sessions (four Quantum DLT-7000 tape drives) and
5-way multiplexing. The database is currently 391 GB.

I've come to the conclusion that I was hitting SSA driver bottlenecks (I had
12 loops on 6 SSA cards, with an average of 24 drives per loop - now I've
got six loops of 48 drives each on six ssa cards). I don't know if it was
the SSA adapters, the device drivers, or the SSA routing processes. All I
know is that the drives would hit 100% busy at 3.4 to 4.6 MB/sec write;
those same drives now go as high as 8 MB/sec write rate before going 100%
busy.

I don't know if this helps any --

Tom Kauffman
NIBCO, Inc

> -----Original Message-----
> From: Masa, Ralf [SMTP:masa.ralf AT COMBIBLOC DOT COM]
> Sent: Thursday, November 04, 1999 9:55 AM
> To:   ADSM-L AT VM.MARIST DOT EDU
> Subject:      SAP-Backint-ADSM
>
> Hi there,
>
> is there anyone with performance-experiences using "Backint 2.4" for
> backing
> up and restoring an SAP/Oracle Database with ADSM ?
> We use a SP2 with a High Performance Switch. The ADSM-Server in there is
> 3.1.2.42 on AIX 4.3.2. We have good performance in saving our Database
> into
> a 3494-Library with 3590 Tapes (~100 GB/h). But we are not able to to tune
> our system to have restore bandwith more than 20 GB/h. The problems only
> occurs whith backint - normal network operations on our HPS performe well.
>
> Any suggestions ?
>
> TIA, R. Masa
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