Discussion:
Db Dumps and Shared Memory Segments
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Venkitachalam
2009-04-09 10:11:05 UTC
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Hi,

I was of impression that if we need to stripe a database dump into say 8
then we need 8 shared memory segments as well. Is it correct?

Is there any link to worker processes and striping?

Thanx in advance
Venki
Bret Halford [Sybase]
2009-04-09 16:01:07 UTC
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Post by Venkitachalam
Hi,
I was of impression that if we need to stripe a database dump into say 8
then we need 8 shared memory segments as well. Is it correct?
Is there any link to worker processes and striping?
Thanx in advance
Venki
No. If you dump with 8 stripes, backup will generate 8 sybmultbuf
processes to do the transfer, but this doesn't have anything to do
with ASE's shared memory segments. You can choose an arbitrary number
of stripes for each dump command (within the limits) without having
to reconfigure memory. You can think of sybmultbuf processes as
"backupserver worker processes", but there is no link to ASE worker
processes.
Mark A. Parsons
2009-04-09 16:31:02 UTC
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Post by Venkitachalam
I was of impression that if we need to stripe a database dump into say
8 then we need 8 shared memory segments as well. Is it correct?
This will depend on the OS under which you're running the backupserver, eg, in UNIX environments some shared memory
[segments] will be needed by the backupserver and/or sybmultbuf processes.

How much shared memory [segments] needed will depend on the number of concurrent dump/load commands as well as the
number of stripes.


Some solved cases @ sybase.com that touch on this subject:


http://search.sybase.com/kbx/solvedcases?id_number=11271468

http://search.sybase.com/kbx/solvedcases?id_number=10942925

http://search.sybase.com/kbx/solvedcases?id_number=10885817

http://search.sybase.com/kbx/solvedcases?id_number=11048125

http://search.sybase.com/kbx/solvedcases?id_number=11079401
Post by Venkitachalam
Is there any link to worker processes and striping?
The shared memory [segments] required by the backupserver and/or sybmultbuf processes has nothing to do with ASE worker
processes or ASE shared memory requirements.
Venkitachalam
2009-04-16 09:24:05 UTC
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Hi All,

Thanks for the inputs.

So to sum up,

1. yes the shared memory segments and stripes have a relation - well
explained in case 11271468
2. worker processes do not come into picture, in case of backup

pls correct if I am wrong.

regards
Venki
Post by Mark A. Parsons
Post by Venkitachalam
I was of impression that if we need to stripe a database dump into say 8
then we need 8 shared memory segments as well. Is it correct?
This will depend on the OS under which you're running the backupserver,
eg, in UNIX environments some shared memory [segments] will be needed by
the backupserver and/or sybmultbuf processes.
How much shared memory [segments] needed will depend on the number of
concurrent dump/load commands as well as the number of stripes.
http://search.sybase.com/kbx/solvedcases?id_number=11271468
http://search.sybase.com/kbx/solvedcases?id_number=10942925
http://search.sybase.com/kbx/solvedcases?id_number=10885817
http://search.sybase.com/kbx/solvedcases?id_number=11048125
http://search.sybase.com/kbx/solvedcases?id_number=11079401
Post by Venkitachalam
Is there any link to worker processes and striping?
The shared memory [segments] required by the backupserver and/or
sybmultbuf processes has nothing to do with ASE worker processes or ASE
shared memory requirements.
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