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Shared memory segment sizes have to be multiples of 262144

 
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bozoz
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Joined: 30 Jul 2006
Posts: 17

PostPosted: Tue Oct 17, 2006 2:00 am    Post subject: Shared memory segment sizes have to be multiples of 262144 Reply with quote

http://groups.google.com/group/comp.databases.informix/browse_thread/thread/9e39d84be5ad0612/b534093bf3ce2afa?lnk=st&q=informix+multiple+shared+segments&rnum=6&hl=en#b534093bf3ce2afa

the important part:


For
Informix the trick is to maximize the use of this memory by having all your
shared memory segments (onstat -g seg) fall on the 256 meg boudaries. This
means your SHMADD must be set to 262144. The same strategy applies to your
SHMVIRTSIZE. You want it to be a multiple of 262144. This values are
critical. For example if you set SHMVIRTSIZE to 524288, two 256 meg
segments will be allocated. If you set SHMVIRTSIZE to 524289, three 256 meg
segments will be allocated. You will lose all the unused memory in the 3rd
segment. It can NOT be used by anything else. In a typical environment,
you are going to lose a good portion of a single segment to the message
portion of share memory. There isn't much you can do about this.
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