Perry:
Thanks for the info --- I've passed this along to the technical support
folks who will be most interested in the MVS TCP/IP stack and multiple
processor info, among other things. I also sat with the network gurus this
afternoon, and it was discovered (isn't it always this way?) a table (or
series of tables) that had pointers telling any specific piece of data
coming across the wire to follow only one specific path to the mainframe.
Unfortunately, that path did NOT include the Cisco router. That simply
meant that any ADSM traffic, no matter what default gateways were
established for them, always went through the impossibly slow IBM 3745
before even getting to the Cisco box and then out to the mainframe. We were
seeing access times of over 1000ms before the change to the tables, and
then 50-140ms times afterward. Better, but not what where it should be....
Of course, this wasn't the miracle cure for all ADSM's network woes, but it
was a start. I suspect there are more hidden tables and similar items along
the way that will require changes before this is all over with. I've also
been watching the thread concerning TCP/IP, and that may end up having some
impact on the network once the dust clears. I'll let you know how things
progress....
C.L.Cannam
Storage Management
GENAM/St. Louis, MO/USA
"McGrew, Perry" <pmcgrew AT AGWAY DOT COM> on 01/23/98 01:41:01 PM
Please respond to "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
To: ADSM-L AT VM.MARIST DOT EDU
cc: (bcc: Cindy Cannam)
Subject: Re: networking and adsm
Cindy,
We are in the midst of ATM & ADSM implementation too. We are running
OS/390
1.3, TCP/IP 3.2, ADSM/MVS V3 and have V3 Clients on our AIX, Novell and
HP-UX
machines. We just installed an IBM 8265 (native ATM switch). We backup to
MVS
via OSA-2 card. Our testing has shown 1.5 - 1.7 MB/sec (approx 5.4 GB/hr)
single threaded. I can FTP over ATM UNIX-to-UNIX at 5-7 MB/sec which
works
out to about 18-25 GB/hr reported. Our throughput "problems" are
basically:
1) We ran Ethernet LAN Emulation (LANE). Ethernet restricts the MTU size
to
1500.
2) Attempted to convert to Token-Ring Emulation because we can increase the
MTU
size to 4544.
The problem here is that HP's don't support Emulated Token-Ring over
ATM.
3a) OSA-2 card on the mainframe doesn't support Classical IP until OS/390
V2 R5
due out in March.
3b) The MVS TCP/IP stack doesn't perform well as UNIX TCP/IP stacks. MVS
TCP/IP (as well
as ADSM/MVS) doesn't take advantage of muliple processors. So even
if
you have a multi-CPU
CMOS box, such as 9672-R53, you are limited to power of a single
processor -- approx 20 MIPS
in our 9672-R53.
4) We have been told to expect about 6MB/sec using ADSM/MVS V3
5) As I understand it, the MVS TCP/IP stack in OS/390 V2R5 (FMID HTCP340)
is
supposed to
be another quantum leap in performance -- which would address 3a.
I can't comment on some of your other issues but we invested a lot of time
and
money in the ATM/ADSM infrastructure. We went to IBM's Networking center
in
Raleigh where they drew up this solution and "promised" that it would meet
our
needs --- to this date it hasn't lived up to anywhere near the throughput
numbers we presented in any of the meetings with them. To their credit,
they
have been working very hard at helping us solve the throughput issue....
Hope this helps a little...
Perry
Agway Inc.
Cindy Cannam wrote:
> To all ADSMers:
>
> Just out of curiosity, how many of you folks are experiencing dreadful
(and
> I mean really horrible) network transfer rates for normal incrementals
from
> your ADSM client nodes to your ADSM server? I've contended all along with
> the network people that a 1st backup of a new NT-based client/node with
> approximately 8GB of data should not take DAYS, and should not experience
> MULTIPLE time-outs --- if you crunch the numbers, the rate is about 0.636
> GB/hour. I'm not a network guru, but even this is much, much lower than I
> had expected when the router was 1st purchased.
>
> Environment: ADSM server - MVS OS/390
> TCP/IP
> 16 Mb Token ring (non-switched)
> Cisco 7000 series router (7507) with one blade dedicated to
ADSM
> traffic only
> Clients: Mostly NT, Lotus Notes on NT, UNIX/Sun, UNIX/AIX, Novell
> (right now only the NT-based machines are being backed up with
> ADSM; the remaining machines are pending implementation --- I don't think
> there's a window BIG enough to handle the backups from the
other
> machines)
>
> I realize there are no network benchmarks available for ADSM given the
> infinite number of network and environment configurations ADSM may run
> under. But I'm most interested in hearing about folks who are
experiencing
> the same thing (and how you're correcting it, if possible), and who out
> there is experiencing great transfer rates (like the guy who had
> 24-25GB/hour via ATM) and would like to share with the ADSM world your
> success story! I'm "building my case" for further investigation.
>
> Thanks much!
>
> C.L.Cannam
> Storage Management
> GENAM/St. Louis, MO/USA
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