I can't run real comparisons to your numbers, but I've been through the
drill with an SP frame and a 3590. Properly tuned, I ran on the ragged edge
of 20 GB/hr to the tape drive. This is just over 5.5 MB/sec - and yet I'm
seeing over a 3:1 compression ratio on the data. (SAP/R3, Oracle 7). In the
same environment, I have been unable to push 100 Mb ethernet above 65 Mbit
regardless of the number of data streams.
I'm now running 3 Quantum DLT-7000 drives for this backup and doing 59.5
GB/hr over the SP switch. (The 3590 went back - we couldn't cost-justify
IBM's price/performance vs. the Quantum DLT price/performance).
Tom Kauffman
Sr. Technical Advisor
NIBCO, Inc.
> ----------
> From: Matthew Emmerton[SMTP:Matthew_Emmerton AT AGORAINC DOT NET]
> Sent: Wednesday, May 27, 1998 7:19 AM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: Performance Issues
>
> We're running ADSM 3.1 on an RS/6000 R50 server (4x604e) with ~150 GB of
> SSA DASD, of which ~60 GB is being backed up daily. We're using a 3590
> drive as our backup device. Oh, and it has 2 GB of RAM.
>
>
> These are some older statistics (when we were backing up less...)
>
> Total number of bytes transferred: 36.02 GB
> Data transfer time: 5,616.98 sec
> Network data transfer rate: 6,724.53 KB/sec
> Aggregate data transfer rate: 1,348.57 KB/sec
>
> How I am interpreting this is that over the network (TCP/IP, 100BaseT
> Ethernet) I'm getting ~6.5 MB/s (around 65% utilization) which is
> acceptable. However, the aggregate (as I'm interpreting it) would be the
> overall throughput of the system. Now, according to the 3590
> documentation, it should be able to back up at up to 9 MB/s. The SCSI-2
> bus driving the 3590 can handle at least SCSI-1 speeds of 10 MB/s. The
> SSA driving our DASD can handle well over SCSI-2 speeds; so the drive and
> network I/O don't seem to be the limiting factor.
>
> What I'm wondering if there is not enough iron behind the ADSM server,
> which is causing the performance problem - that is, why we can only back
> up
> 1.3 MB/s when all of the subsystems can handle more. We've tried all
> kinds
> of performance optimizations on our TCP/IP settings, as well as using over
> 512 MB of RAM for ADSM cache, with minimal performance improvement. We've
> tried the stuff in the ADSM Performance Tuning Guide (v3) and the folks
> from IBM don't seem to have any clear-cut answers.
>
> What I'd like to know is if a) anyone else has had similar types of
> performance problems and b) what is a decent typical backup speed? Am I
> being too ambitious in wanting ~9MB/s?
>
> --
> Matthew Emmerton, System Administration
> Agora Food Merchants, National IT
> +1 (905) 565-4231
>
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