[p4] Slow Downs - More RAM?

[Russell C. Jackson]

A company I work for has Perforce running on a Dell with 2 dual core 
processors, 8 gigs of RAM and Windows 2003 Advanced server 64 bit with 
64 bit Perforce. They are using a Hitachi AMS 1000 to host both the 
metadata and the depot data volumes. They have 2600 users on that 
server, and it runs quite well. As of 2006.2, Perforce has eliminated 
the one remaining problem Windows had, and that was a file handle limit 
because of the POSIX API they were using. That said, we are still moving 
to Linux because you can monitor your server much better on Linux and 
determine what is causing problems better on Linux.

There are several things that help, but one key is that we have 
maxscanrows and maxresults both set to prevent users from running 
excessively large operations that back the server up the way you 
described yours is doing. Another is the very fast SAN. Perforce's 
performance is very drive speed dependent. What is happening to your 
server is exactly what Perforce said. Someone has run a very large 
command, and locked the database files. All other transactions backup 
and wait on that lock to release, and then they quickly go through. The 
order of things that will help you:

Memory
Drive Speed (If you have more memory than the size of your db files, 
then the CPU speed is the second thing on this list instead of the third.)
CPU Speed

All three of these affect Perforce's performance, and if one is causing 
the bottle neck, increasing the other two won't help. I have seen many 
teams try to prove a particular upgrade can be justified before spending 
the money, but it is a nearly impossible task. You just have to know 
that the faster you have of the three things above, the faster Perforce 
will perform, but you still have to take actions inside of Perforce, and 
in your process to prevent your users from killing your server with 
excessively large requests.

Also, consider breaking your server into multiple instances if you can. 
If you have independent product lines that can operate in independent 
servers, you can improve performance by splitting those into two or more 
Perforce servers, both running on the same hardware you have now, and 
get better performance than the single instance you have running on that 
hardware.

Thanks,
Rusty

--------------------------------------------------
RCJackson Consulting
Perforce Consulting Partner and Certified Trainer
--------------------------------------------------
rusty at rcjacksonconsulting.com
http://www.rcjacksonconsulting.com
tel:      479-696-9710
fax:      479-967-0963
mobile:   479-747-3845
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Terry Metler wrote:
> I need opinions about hardware and how "big" I need to go...
>
>  
>
> We've been running Perforce now for about 7 months.  Up to November
> everything was running very smoothly but since then we have many slow
> downs a day.  There are no indications on the system except that I have
> noticed just before everything goes back to normal that the cores all
> peg to 100% utilization for a few seconds.  This has slowly gotten worse
> to now it is happening two or three times a day.
>
>  
>
> After talking with Perforce support they indicated that it looks like a
> case that the server is running out of resources.  There are points when
> there are over 700 concurrent transactions.  Support mentioned that it
> looks like a large process is backing everything up and eventually it
> does finish and everything else runs really fast that was backed up
> behind that one process.  
>
>  
>
> I've rebuilt the databases, defragged the drives, removed the audit file
> and moved the database files to a separate drive to try and get some
> additional performance.  None of these have made a significant
> improvement.
>
>  
>
> Currently...
>
> Users: 160
>
> Files: 460 000 (not including all revisions)
>
> Server
>
>             CPU: 2 x 3.0Ghz Xeon
>
>             RAM: 4GB
>
>             OS: Windows Server 2003 Standard
>
>  
>
> New server I'm looking at...
>
> CPU: 2 x 2.6Ghz Opteron
>
> RAM: 32GB (Can be upgraded to 64GB)
>
> OS: Windows Server 2003 Enterprise
>
>  
>
> I am hoping to hear from some people that have been using Perforce for a
> lot longer than we have.  I don't want to purchase a bigger server and
> not get the performance I'm being told I would get with "a lot more" RAM
> (the current one is almost maxed out physically and is maxed with the
> Standard OS).  All recommendations are more than welcomed as I want to
> have a better feeling that it is the hardware that is causing the slow
> downs before shelling out for a new server.
>
>  
>
> Thanks in advance for your recommendations and feedback!!
>
>  
>
>  
>
> Terry
>
>
>
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