Informix Throughput
A user running IDS 9.21 on HP-UX asked how many 800MHz CPUs in an RP4440 would be needed to match the throughput of their existing N4000 with 8 x 440MHz CPUs — whether 4–8 would do. After a joke reply giving a bogus precise number, Art Kagel explained it comes down to the usual trade-off between fewer fast CPUs and more slower ones: simple queries, few concurrent users, no fragmentation and PDQPRIORITY=0 favour fewer, faster CPUs, while many users, multi-table queries, fragmented tables/indexes and PDQPRIORITY>2 favour more CPUs. No specific CPU count was agreed; the poster must judge where their workload sits.
Auto-generated by DrWatson from the posts below — may be imperfect; read the full thread.
IDS9.21.FC4 HPUX11.0 Hello All, We have an N4000 with 8 x 440MHz cpu's. How many 800Mhz cpu's would we need in a RP4440 to achieve the same level of throughput. Assuming same memory etc. Would we need the full 8 or would somewhere between 4 and 8 suffice. Thanks in advance, Howard
"howie" <howie_lfc@hotmail.com> wrote in message news:f69783ad.0403230045.340ceaf0@posting.google.com... > IDS9.21.FC4 > HPUX11.0 > > Hello All, > > We have an N4000 with 8 x 440MHz cpu's. How many 800Mhz cpu's would we > need in a RP4440 to achieve the same level of throughput. Assuming > same memory etc. Would we need the full 8 or would somewhere between 4 > and 8 suffice. > > Thanks in advance, > > Howard 7.1642577299940029156447
On Tue, 23 Mar 2004 03:45:54 -0500, howie wrote: > IDS9.21.FC4 > HPUX11.0 > > Hello All, > > We have an N4000 with 8 x 440MHz cpu's. How many 800Mhz cpu's would we need > in a RP4440 to achieve the same level of throughput. Assuming same memory > etc. Would we need the full 8 or would somewhere between 4 and 8 suffice. This is the old tradeoff between faster processors or more processors. Both have their uses. If your queries are simple, you have a relatively small number of concurrent users, and you do not have any fragmentation and you always run with PDQPRIORITY=0 then faster cpus are always better so you can get away with fewer faster CPUs for the same performance. At the other extreme if you have very many concurrent users, your queries tend to access several tables, most large tables are fragmented as are your indexes, you always run with PDQPRIORITY>2 then the more CPUs you throw at the problem the better, even if they're a bit slower. So to address your question. Since you're getting faster CPUs anyway, judge where you are on the continuum above and select a cpu count accordingly. Art S. Kagel