Archives of the TeradataForum
Message Posted: Tue, 08 Nov 2005 @ 19:02:43 GMT
| Subj: | | Re: ARCMAIN throughput - limiting factors |
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| From: | | John Graas |
Anomy.Anom wrote:
| | My response: We have just one TDP connected to two mainframe hosts or LPARs. We do have multiple ESCON channels on the mainframe however.
Since it has been made clear to me that a single backup job uses only one ESCON connection, and given the limits on ESCON throughput that I have
seen, that would appear to be our limiting factor. | |
I don't think this is quite correct. A single backup job will use all ESCON connections defined to the backup's TDP between the Teradata
configuration and the mainframe. Each ESCON has a 30GB/hour realized throughput maximum (double this for FICON). The aggregate of all ESCON
connections in play is the throughput maximum of the interconnect between the Teradata configuration and the mainframe.
I think the previous poster was trying to point out the single path limit between the mainframe and the backup device being written to by the
backup job. That is, a single backup job can only write to one backup device. If this backup device's (e.g. tape) capacity is less than the
aggregate throughput of the interconnect between the Teradata configuration and the mainframe, then this will be the limiting factor.
The reason that "cluster backups" were mentioned previously is that one can run multiple backup jobs in parallel, each backup job archiving a
section or "cluster" of the Teradata configuration, writing to multiple backup devices in parallel. Thus the aggregate throughput of the target
media is increased to match the capabilities of the Teradata configuration.
jdg
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www.jgraas.com
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