Conference 7.286::fddi

    What systems are you backing up from/to?

    Backup from VAX6420 to VAX6620 or vice versa. Only one of the VAX6000
    will have a tape drive and these two system will not be cluster as 
    there is critical appliaction running on one of the system.
    
    Customer would like to take the advantage of the 100Mb FDDI ring
    between the two VAX6000 to perform the daily BACKUP. Several tests
    has been done such as files copy over FDDI seen slower than the 10Mb
    ethernet. I have notices that file copy tend to stay at 100byte/block
    by examine the line counters. I don't have changes to test teh BACKUP
    from disk to disk or other medias. I need to know the following:-
    
    1. Why file copy id slower ?
    2. Will BCAKUP throught be better over FDDI as compare to 10Mb ethernet
       ? Any statics to show customer ?
    3. A recommended solution to customer such that the backup must be
       faster  and as best fully utilize the FDDI bandwidth.
    
    Thanks
    Parry

In doing the backups, are you running the backup on the system with the tape
drive, and MSCP-serving the disks to that system, such that you're "pulling"
the data across the FDDI, or are you running the backup on the system with the
disk drives, and TMSCP-serving the tape drive to that system, such that you are
"pushing" the data across FDDI?

What maximum size is currently enabled for packets on the FDDI?  (In other
words, have you raised LRPSIZE {for pre-V6.0} or NISCS_MAXPKTSZ {for V6.0 or
later}?)

Do you have the option of running multiple backups at once, as a way to utilize
more of the FDDI ring's bandwidth?

    Hi, 
    Sorry for not be able to reply, answer to .-1 as below :-
    
    1. We on;y try BACKUP from DISK to DISK only.
    2. The LRPSIZE has setup as require for FDDI operation.
    3. The 10 Mb ethernet controller is connected but is set to OFF state.
    4. Has also try setup RAM disk for backup between the two system but
       the improvement is so little that using FDDI doesn't indicate good
       improvement over the 10Mb ethernet.
    
    It will be good if there is a reference setup on both hardware and
    software and any limitation as well as backup thougthout.
    
    Anyone out there has setup FDDI ring with and without bridge to 10Mb
    ethernet and perform backup operation using the FDDI ring ?
    
    Thanks
    Parry 
    
    
    
        Backup from VAX6420 to VAX6620 or vice versa. Only one of the
    VAX6000
        will have a tape drive and these two system will not be cluster as
        there is critical appliaction running on one of the system.
    
        Customer would like to take the advantage of the 100Mb FDDI ring

        This sounds like the duplicate MAC address problem again.  As was
    pointed out in 1459.5, setting DECnet off is insufficient.

    re .-1:
    
    I follow the 1459.4 and search on the ANA/SYS and found that on one of
    the node that the FDDI(FXA) and ethernet(ETA) has the DECNET(60-03)
    same MAC address but the ETA state is "OFF". I need to confirm if by
    purgeing away the BNA line/circuit will help on BACKUP speed over FDDI
    or assume that this condition what will happen where perform BACKUP
    from two systems.
    
    Thanks
    Parry

        The problem is not that the DECnet protocol is enabled for both
    interfaces, it is that the MAC address is the same as a result of the
    way Phase IV DECnet uses the interfaces.  The configuration is wrong as
    it stands, and I would certainly expect problems as a result of the
    misconfiguration.  Stop running DECnet on the ethernet (as 1459.*
    suggests).  Follow the instructions in 1459.5
    
        Whether or not you have other problems as well is hard to tell. 
    Fix the known problem and see.  This is the most likely cause.

No the problem here is that DECnet uses 1500 byte packets regardless
of whether  it is ethernet or FDDI and on this particular setup
the 6400 is compute bound while doing the backup so the application
is not passing buffers fast enough to the network so the performance
is about the same.      Unless someone known of anything else he could
tune on the system, I don't think he can do better with FDDI.

Maureen

If the two systems could be clustered at least during the time the backup is
being done, SCS would be able to take advantage of the larger ~4500-byte packet
size.

    I could understand that BACKUP via NETWORK will pass the data with all
    the overhead added via the network layers. Ideally, LAVC via FDDI could
    cut down certain amount of overheads. But the customer has critical
    application running on one of the system and so clustering is out.
    
    Is there any better solution for backup via FDDI(assume that customer 
    want to take the advantages of FDDI speed) ?
    
    I will get the engineer to purge the BNA circuit/line from the DECNET
    database and tryout BACKUP using FDDI again.
    
    Thanks
    Parry