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From:Benjamin Pflugmann Date:January 7 2000 1:46am
Subject:Re: Request for opinions regarding perfomance (LONG)
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On Wed, Jan 05, 2000 at 05:28:17PM -0500, lgr@stripped wrote:
> All inserts would be done to the master server and then replicate to
> the slaves.  The application will be about 80%/20%
> SELECTS/(UPDATES+INSERTS) so this should work well. Most of the
> selects will be on 1 of 2 large tables (with occasional joins) with
> up to 200,000 records.

It's hard to comment on this type of usage information because there
are still too many open variables...

> Pentium III (or AMD Athlon if the upcoming motherboard offerings are
> good)  800MHZ or more --hopefully > 1GHZ :)

I would forget about MHZ, except if you want to throw out your
money. 800 vs. 500 theoretically gives you 60%, but in practice you
can be glad if you get 20% out of it. Rather get a dual board with to
slower CPU (which costs about the same as the single fast CPU) and you
will get about 80% or more with MySQL on a SMP system.

Or in other words: If CPU is going to be a bottleneck for your
application, those 20% won't help much.

> 1024MG RAM


> 3x Adaptec 2940U2W SCSI Controller
> 	1 SCSI-SCSI RAID CONTROLLER  (most likely Mylex)  128MB CACHE --Write
> Back, 72 Hour Battery Backup for Cache Memory
> 	2x9GB 10,000 RPM U2W Drives (Configured as RAID 1) for OS files -- this
> will be the boot partition) connected to controller #1
> 	5*18GB 10,000 RPM U2W Drives (RAID 5 for MySQL Database files)
> connected to controller #2
> 2x4GB 10,000RPM U2W Drives connected to controller #3 (each configured
> as swap)  (I don't think i'll really need 8GB of swap, but it's really
> nice to  split your swap across multiple drives  

I, personally, would say, forget caring about your swap. If your
database server starts swapping you can consider your server gone (if
it continuously get hits), because it slows it down soooo much and you
will get a cascade effect from the new requests coming in.

Believe me, I saw servers going down this road... (I wasn't the
administrator, hehe ;-)

If you get to swapping, either upgrade your hardware or limit the
resources MySQL is allowed to use. By the latter way you will get
rejected requests, but at least your server lives on and will handle
the majority of requests.

> A really high quality 100MB Ethernet Card (Intel something or other -- i
> don't have the model handy)
> --
> Does anybody have any performance stats on an Athlon???

At same MHZ it's faster than any other x86 CPU *which is available*
(note the emphasis), only a little bit faster than the corresponding
Pentium III. This may change in the coming months. But as said above,
if CPU is going to be your bottleneck, a single CPU won't solve your
problem, IMHO.

Of course, there are a lot faster CPU's than x86 available (Alpha, ...).

> Is this enough RAM?

Well, I tend to say, with databases you cannot have enough memory. 

But more serious, you might try to start with less and see whether
that already fits your needs. Depending on the size of a record in
your databases I would either start with 256MB or 512MB.

> I'm leaning strongly toward running FreeBSD (more on this below) as I am
> much more competent with it (I haven't touched a Linux kernel since
> 1.2.12).
> FreeBSD isn't going to use MySQL on multiple processors (damn those
> userland threads), but would it still be to my benefit to use an
> System??

Sorry, I don't know FreeBSD good enough to give an authoritative
answer, but from what I read on the mailing list, I guess, that
FreeBSD don't get much from the second CPU, if you are mainly running
one program (the MySQL server).

Nevertheless I would suggest to start with what you are comfortable
with and follow the suggestion of Sasha and the others and test
whether that would do the job. If a single processor machine can't
cope with the load, you can still start looking for another OS.



> ----
> <I don't mean to begin a holywar, but I must ask for peoples opinions>
> >From what I have gathered from the mailing list archives about MySQL
> performance on FreeBSD & Linux  (correct me if I am wrong), FreeBSD has
> a bit better disk access, Linux is a bit faster (due to kernel threads),
> but FreeBSD degrades more gracefully under HEAVY load.  Linux also
> performs better in SMP as it has kernel threads (vs userland) so MySQL
> threads can run on more than 1 processor.  The bottom line after
> everybody has finished their pokes and jabs is: go with which ever you
> are more comfortable with.
> Does anybody have any reason why Linux would be a signifigantly better
> choice in this particular implementation?
> </holywar>
> I thank you all for your time and thought
> Leonard Rosenbeck
> lgr@stripped
> -- 
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Request for opinions regarding perfomance (LONG)Leonard Rosenbeck6 Jan
  • RE: Request for opinions regarding perfomance (LONG)Cheng-Wei Cheng6 Jan
    • RE: Request for opinions regarding perfomance (LONG)sinisa6 Jan
  • Sequential UpdatesCheng-Wei Cheng6 Jan
    • Re: Sequential UpdatesSasha Pachev6 Jan
  • Re: Request for opinions regarding perfomance (LONG)Sasha Pachev6 Jan
    • Re: Request for opinions regarding perfomance (SHORT)Mark Zieg6 Jan
  • Re: Request for opinions regarding perfomance (LONG)Benjamin Pflugmann7 Jan
    • How do I..Cheng-Wei Cheng7 Jan
      • Re: How do I..sinisa7 Jan
      • Re: How do I..Paul DuBois7 Jan
Re: Sequential UpdatesSasha Pachev6 Jan