| Title: | FDDI - The Next Generation |
| Moderator: | NETCAD::STEFANI |
| Created: | Thu Apr 27 1989 |
| Last Modified: | Thu Jun 05 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 2259 |
| Total number of notes: | 8590 |
I have a question about throughput regarding FDDI vs. ETHERNET 802.3.
I manage a data center that performs all file and disk backups over the
network using RSM. We are currently backing up about 125 spindles per
night. I have a 3 node VAXcluster with 2 HSC70s and a lot of RA90 and RA92
disks which are used as storage tanks to hold the data until the next
morning when it is transferred to TA90 tape cartridge. The following is a
small picture of my cluster......
------------ --------- ------
| | | | | |
| VAX 8650 | | 6420 | |8550|
| | | | | |
------------ --------- ------
\ | /
------ ------
|HSC | |HSC |
| 70 | | 70 |
------ ------
----- ----- ----- -----
| | | | | | | |
|SA | |SA | |SA | |SA |
|600| |600| |800| |800|
| | | | | | | |
----- ----- ----- -----
My network includes a Main Site Segment (MSS BACKBONE) with 4 segments
hung off of that which are classified by groups and the projects they
work on. The MI1 segment contains mostly time-share and public systems.
The MI2 and MI3 segments contain systems which are primarily used for
software development and testing. And the IP segments contains all Ultrix
systems. My backup cluster shown above sits on the the MSS site backbone.
Right now we are pushing 80+% utilization on the MSS segment and around
30-40% utilization on the MI1 and MI2 segments during the night when backups
are running. We currently get a lot of failures due to contention in the
MSS segment and things are not finishing in their allotted time slots. Backups
run from 8:00 p.m. until 8:00 a.m.. We would like backups to finish around
6:00 but they sometimes will run past 9:00 a.m..
I'm looking for some data that will support my theory that if I upgrade
just the Main Site segment for now to FDDI and install a DEMFA on my 6000
system I will notice a significant improvment in the time it takes to perform
these backups. Can anyone point me to some documentation that will or will not
support this? Also is there anyone I can talk with off-line regarding this
upgrade?
Thanks in advance for any help.
Larry Britt
TP East Computing Services
TAY1 Littleton, Mass
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 562.1 | Is this what you want to do? | KYOA::KOCH | It never hurts to ask... | Fri May 08 1992 11:56 | 35 |
Well, can you give us a generic layout of the network segments?
In general, if an FDDI is on the 6420 and you use a 3-port bridge to
connect the segments to the 6420, you will get be able to get the 3
segments into the 6420 running full speed. At this point, you may
saturate the 6420. Is backup using DECnet as a transport for RSM? If
so, you will be running DECnet over the FDDI controller as opposed to
the Ethernet.
------ Seg 1 ------ ------ Seg 2 ------ ------ Seg 3 ------
^ ^ ^
| | |
-------------------------------------------------
| FDDI 3 Port Bridge |
-------------------------------------------------
^
|
v
---------------------
|DECconcentrator 500|
---------------------
^
|
v
------------
| 6420 |
| FDDI |
------------
|
|
*
You would need to connect the other CI machines to the bridges for
Ethernet connection to the 6420. Is this what you want to do?
| |||||
| 562.2 | Yes, thats pretty much what I want to do.. | JMSBND::BRITT | The Node is BOND...JMSBND | Mon May 11 1992 09:10 | 8 |
Yes, that is what I want to do except I would 2 or 3 (FDDI 3 Port
Bridges) and I would only use 1 or 2 of the ports on each bridge.
That way I wouldn't saturate the bridge and I would have spare ports in
case we had a port failure.
Yes I am using DECNET as a transport for RSM.
Larry
| |||||