Re: [GENERAL] Question on Opteron performance
Reece Hart wrote: On Wed, 2004-03-10 at 18:23, William Yu wrote: /At this time, only Newisys offers a Quad Opteron box and it carries a hefty premium. (Sun's upcoming 4X machine is a rebadged Newisys machine and it's possible HP's will be also.)/ There are several vendors with quad opterons out there. Off the top of my head, I know that Aspen, Penguin Computing, Appro, and Polywell all have them. I just googled quad opteron and see that there are bunches of others too. I'm pretty sure most of these guys just rebadge the Newisys box (at this time). ---(end of broadcast)--- TIP 8: explain analyze is your friend
Re: [GENERAL] Question on Opteron performance
On Wed, 2004-03-10 at 18:23, William Yu wrote: At this time, only Newisys offers a Quad Opteron box and it carries a hefty premium. (Sun's upcoming 4X machine is a rebadged Newisys machine and it's possible HP's will be also.) There are several vendors with quad opterons out there. Off the top of my head, I know that Aspen, Penguin Computing, Appro, and Polywell all have them. I just googled quad opteron and see that there are bunches of others too. -Reece -- Reece Hart, http://www.in-machina.com/~reece/, GPG:0x25EC91A0 0xD178AAF9
Re: [GENERAL] Question on Opteron performance
On Wed, 10 Mar 2004, Christopher Petrilli wrote: > On Mar 10, 2004, at 3:14 PM, Steve Wolfe wrote: > > >Before I shell out the $15k on the 4-way Opteron, I'm going to spend > > some long, hard time looking for ways to make the system more > > efficient. > > However, after all that's already been done, I'm not optimistic that > > it's > > going to preclude needing the new server. I'm just surprised that > > nobody > > seems to have used PostgreSQL on a quad-Opteron before! > > Well, I haven't had a chance to run PostgreSQL on a quad-Opteron box, > but in discussing this with someone building a cluster out of them, > their experience is that they are seeing better performance out of a > quad-Opteron than a 3Ghz Xeon box (quad as well), which they believe > reflects superior memory architecture. So, if someone has run on a > quad-Xeon of similar "specs", then I would imagine you should see > similar, if not better, numbers. This article: http://www.anandtech.com/IT/showdoc.html?i=1982 seems to support that view that opterons currently scale better than Xeons. ---(end of broadcast)--- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
Re: [GENERAL] Question on Opteron performance
> "SW" == Steve Wolfe <[EMAIL PROTECTED]> writes: SW> However, after all that's already been done, I'm not optimistic that it's SW> going to preclude needing the new server. I'm just surprised that nobody SW> seems to have used PostgreSQL on a quad-Opteron before! I think people saturate the disks before the CPUs. I know I certainly do, even with 4GB RAM and a fair number of shared buffers. Dual CPUs are more then plenty for our usage patterns. -- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Vivek Khera, Ph.D.Khera Communications, Inc. Internet: [EMAIL PROTECTED] Rockville, MD +1-301-869-4449 x806 AIM: vivekkhera Y!: vivek_khera http://www.khera.org/~vivek/ ---(end of broadcast)--- TIP 6: Have you searched our list archives? http://archives.postgresql.org
Re: [GENERAL] Question on Opteron performance
With mem per CPU, Opterons scale very well in most cases (as long as you have many processes). The lower memory latency helps too. Is it likely for you to be network bandwidth limited - e.g. maxing out your NICs or NIC I/O capacity? I doubt it, but if you are actually getting close then things get a bit harder... BTW in most Opteron configs, a lot of the major I/O goes through via one CPU. Check this out: http://www.aceshardware.com/read.jsp?id=6277 The benchmarks could be interesting too. At 05:06 PM 3/8/2004 -0700, Steve Wolfe wrote: The main question in my mind is whether a 4-way Opteron is going to give me enough of a performance benefit over a 2-way Opteron to make the extra $10k worth it. My first guess was that it would, as going from 2 Opterons to 4 will give you twice the potential memory bandwidth. However, as PostgreSQL pulls heavily from the global buffers, I may not be able to utilize all of that potential bandwidth. If anyone has done tests with PostgreSQL on 2- vs. 4-way machines under heavy load (many simultaneous connections), I would greatly appreciate hearing about the results. Steve Wolfe ---(end of broadcast)--- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
Re: [GENERAL] Question on Opteron performance
On Mar 10, 2004, at 3:14 PM, Steve Wolfe wrote: Before I shell out the $15k on the 4-way Opteron, I'm going to spend some long, hard time looking for ways to make the system more efficient. However, after all that's already been done, I'm not optimistic that it's going to preclude needing the new server. I'm just surprised that nobody seems to have used PostgreSQL on a quad-Opteron before! Well, I haven't had a chance to run PostgreSQL on a quad-Opteron box, but in discussing this with someone building a cluster out of them, their experience is that they are seeing better performance out of a quad-Opteron than a 3Ghz Xeon box (quad as well), which they believe reflects superior memory architecture. So, if someone has run on a quad-Xeon of similar "specs", then I would imagine you should see similar, if not better, numbers. Chris -- | Christopher Petrilli | petrilli (at) amber.org ---(end of broadcast)--- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
Re: [GENERAL] Question on Opteron performance
> The only time I've seen high cpu and memory bandwidth load with near-zero i/o > load like you describe was on Oracle and it turned out to be an sql > optimization problem. > What caused it was a moderate but not very large table on which a very > frequent query was doing a full table scan (= sequential scan). The entire > table was easily kept in cache, but it was large enough that merely scanning > every block of it in the cache consumed a lot of cpu and memory bandwidth. I > don't remember how large, but something on the order of a few thousand records. Every so often, I log all queries that are issued, and on a seperate machine, I EXPLAIN them and store the results in a database, so I can do analysis on them. Each time, we look at what's using the greatest amount of resources, and attack that. Believe me, the "low-hanging fruit" like using indexes instead of sequential scans were eliminated years ago. : ) Over the past four years, our traffic has increased, on average, about 90% per year. We've also incorporated far more sources of data into our model, and come up with far more ways to use the data. When you're talking about exponential traffic growth combined with exponential data complexity, it doesn't take long before you start hitting limits! Before I shell out the $15k on the 4-way Opteron, I'm going to spend some long, hard time looking for ways to make the system more efficient. However, after all that's already been done, I'm not optimistic that it's going to preclude needing the new server. I'm just surprised that nobody seems to have used PostgreSQL on a quad-Opteron before! steve ---(end of broadcast)--- TIP 7: don't forget to increase your free space map settings
