Re: 32-bit vs AMD64 on Opteron for LAMP server
Quoting Neil Gunton <neil@nilspace.com>:
michael@estone.ca wrote:
I don't have any facts or numbers to bring forward, but you probably
won't notice that much of a difference.
What do you base this opinion on?
Nothing really,
I've setup a handful of amd64 servers and a whack of i386 ones.
Alot of them web servers running basic php and mysql stuff.
Speeds "felt" the same.
Having said that, I would say go for the AMD64 port.
I don't think the install is anywhere near less
straightforward than the 32bit port.
The AMD64 port is less straightforward because they do not include the
dpt_i2o driver, which is necessary for my RAID card. Instead, I have to
either use the i2o_block driver, which I gather has had some
reliability issues under load, or else build a patched kernel with
dpt_i2o, which isn't ideal since it always complicates and lengthens
the install. Also, for some reason, my own kernels always seem to end
up being slower than the stock kernels, even though I am careful to go
through and build in/enable everything very specific to the hardware.
Ah, yes. If your missing some hardware drivers, it can be a pain.
But since you are running 4 Gig of RAM, take full advantage of it by
running amd64.
My understanding is that 32-bit can utilize up to 4 GB as well, it's
when you have more than 4GB that it starts to matter.
I always thought that 32 bit sarge with 4G ram, would only show about
3.3G of available RAM. I could be wrong, and perhaps this doesn't
happen in etch.
Oh, and I would ask you if you have considered Software raid instead
of using an adaptec raid card? If you have time, try benchmarking
between them.
You might be suprised to see which one actually works better for you.
I don't know why it would be faster to use up my main CPU cycles doing
RAID rather than using the hardware RAID that is already in the box.
The guy that built my server seemed to think that this RAID solution
was very appropriate for this setup. In any case, see my previous
paragraph - I won't have time to mess around with testing different
setups. Also, from what I have seen of software RAID in linux, you
still have to mess around with making a new kernel with the RAID
personalities built into the kernel (rather than modules) to be able to
boot off a software RAID partition. The Adaptec makes it all
transparent to me, the 4 drives appear as one single drive and RAID 10
is done under the covers.
Does anybody else have any opinions on whether software RAID would be
faster than using the built-in Adaptec SmartRaid 2015S card?
Etch has full SW raid support right out of the install. No messing
with kernels.
You can even install raid on the / during the install if you wanted.
I didn't want to get into a hardware vs software raid conversation,
but figured if you had a few days of down time, it would nice to run
some tests before hand.
Cheers,
Mike
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