[p4] Slow Downs - More RAM?

[Brad Holt]

Yeah, I'm one of those sites.  Years ago we split up the traffic to
different channels for journal, metadata, versioned files, etc.  It made
a nice difference for quite a while, but eventually we hit that memory
block.  We didn't have the *nix option for our server, so I went with
Win2003 64bit OS, 16GB RAM, with p4 2006.1 and it cleared things up
pretty well (the p4 install was painless and autodetected 32 vs 64).  As
a sloppy benchmark, I've got millions upon millions of versioned files
and just shy of 100GB of metadata (depending on when I last did a
metadata refresh).  Anyway, I don't know if you need to make that leap
yet, but it was clear to me that the 2GB application space limit was
doing us in.

Not that things are that much faster from day to day (they are
somewhat), but the capacity choke ups don't happen anymore.  Still, it
doesn't seem to fully take advantage of the available physical memory.
I guess memory management is something I will never understand...  I
still don't get why I'll have 16GB of available RAM, but a process
(including many p4 processes) will still cause thrashing.  Why doesn't
it just use the available RAM instead of swapping pages on disk?

How large is your metadata?  In particular your db.rev?  Also, what is
that "large process that is backing everything up" that you mentioned?
Disabling our IT backup processes made a nice difference as well.  I now
have them just backup my backups (the nightly checkpoints or journals
truncations + archive file copies).  Also make sure that your virus
scanner is set to ignore the p4 data locations, especially the metadata
(P4ROOT).

Good luck.

-----Original Message-----
From: perforce-user-bounces at perforce.com
[mailto:perforce-user-bounces at perforce.com] On Behalf Of Robert Cowham
Sent: Monday, January 08, 2007 2:28 AM
To: 'Terry Metler'; perforce-user at perforce.com
Subject: Re: [p4] Slow Downs - More RAM?

I know of at least a couple of larger sites running on Windows that have
had
performance problems, and indeed stability problems.

Perforce now say the following:

http://www.perforce.com/perforce/technotes/note077.html

Windows Version Limitations

The Windows 32-bit platform (including Windows 2000 and 32 bit versions
of
Windows 2003 and XP) has a 2GB per-process memory utilization limit. On
Windows, the Perforce Server runs as a single process, servicing each
client
request as a thread within that process. For sites with a very large
transaction volume, this 2GB limitation can inhibit performance and
large
operations. The Windows 64-bit platform does not have this memory
limitation. The use of a 64-bit version of Windows is preferable for
sites
that might encounter the 2GB per process limitation of the 32-bit
version.  


One site cured their issues by a move to Linux, and another site is
moving
to Unix but has not yet fixed on platform. That said, database locks can
always cause backups whatever the platform, so you get approaches like
Google presented at the European conference to avoid those.

Robert

> -----Original Message-----
> From: perforce-user-bounces at perforce.com 
> [mailto:perforce-user-bounces at perforce.com] On Behalf Of Terry Metler
> Sent: 08 January 2007 02:38
> To: perforce-user at perforce.com
> Subject: [p4] Slow Downs - More RAM?
> 
> 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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