Well, that's of course really hard to tell. From personal experience in
a read-mostly environment, the subtop woodcrest 5150 (2.6Ghz)
outperforms the top dempsey 5080 (3.7Ghz, in the same system) by quite a
nice margin. But that dempsey already has the faster FB-Dimm memory and
a much wider FSB compared to your 3.06Ghz Xeons.
But if we assume that the 3.7Ghz 5080 is just the extra mhz faster (~
25%), for a single (dual core) 3Ghz Woodcrest you might already be
talking about a 50% improvement in terms of cpu-power over your current
set-up. Of course depending on workload and its scalability etc etc.
In a perfect world, with linear scalability (note, a read-mostly
postgresql can actually do that on a Sun fire T2000 with solaris) that
would yield a 200% improvement when going form 2 to 4 cores. A 70-80%
scaling is more reasonable and would still imply you'd improve more than
150% over your current set-up.
Please note that this is partially based on internal testing and partial
on assumptions and would at least require more real-world testing for a
app more similar to yours.
As soon as we're publishing some numbers on this (and I don't forget),
I'll let you know on the list. That will include postgresql and recent
x86 cpu's on linux and should be ready soon.
Best regards,
Arjen
On 18-8-2006 21:51, Kenji Morishige wrote:
Thanks Arjen for your reply, this is definitely something to consider. I
think in our case, we are not too concerned with the tech image as much as if
the machine will allow us to scale the loads we need. I'm not sure if we
should worry so much about the IO bandwidth as we are not even close to
saturating 320MB/s. I think stability, reliability, and ease-of-use and
recovery is our main concern at the moment. I currently am runing a load
average of about .5 on a dual Xeon 3.06Ghz P4 setup. How much CPU
performance improvement do you think the new woodcrest cpus are over these?
-Kenji
On Fri, Aug 18, 2006 at 09:41:55PM +0200, Arjen van der Meijden wrote:
Hi Kenji,
I'm not sure what you mean by 'something newer'? The intel
woodcrest-cpu's are brand-new compared to the amd opterons. But if you
need a 4-cpu config (I take it you want 8-cores in that case), Dell
doesn't offer much. Whether something new will come, I don't know. I'm
not sure when (or if?) a MP-Woodcrest will arrive and/or when Dell will
start offering Opteron-servers.
Sas has been designed as the successor to SCSI.
As I see it, SAS has currently one major disadvantage. Lots of new
servers are equipped with SAS-drives, a few nice SAS-raidcontrollers
exist, but the availability of external enclosures for SAS is not
widespread yet. So your options of going beyond (say) 8 disks per system
are a bit limited.
There are of course advantages as well. The bus is much wider (you can
have 4 lanes of 3Gbps each to an enclosure). You can mix sas and sata
disks, so you could have two arrays in the same enclosure, one big
storage bin and a very fast array or just use only sata disks on a sas
controller. The cabling itself is also much simpler/more flexible
(although using a hot-plug enclosure of course shields you mostly from
that).
But whether its the right choice to make now? I'm not sure. We weren't
to fond of investing a lot of money in an end-of-life system. And since
we're a tech-website, we also had to worry about our "being modern
image", of course ;)
The main disadvantage I see in this case is, as said, the limited
availability of external enclosures in comparison to SCSI and Fibre
Channel. HP currently only offers their MSA50 (for the rather expensive
SFF disks) while their MSA60 (normal disks) will not be available until
somewhere in 2007 and Dell also only offers one enclosure, the MD1000.
The other big players offer nothing yet, as far as I know, while they
normally offer several SCSI and/or FC-enclosures.
There are also some third-party enclosures (adaptec and promise for
instance) available of course.
Best regards,
Arjen
On 18-8-2006 21:07, Kenji Morishige wrote:
Thanks Arjen,
I have unlimited rack space if I really need it. Is serial/SAS really the
better route to go than SCSI these days? I'm so used to ordering SCSI that
I've been out of the loop with new disk enclosures and disk tech. I been
trying to price out a HP DL585, but those are considerably more than the
Dells. Is it worth waiting a few more weeks/months for Dell to release
something newer?
-Kenji
On Wed, Aug 09, 2006 at 07:35:22AM +0200, Arjen van der Meijden wrote:
With such a budget you should easily be able to get something like:
- A 1U high-performance server (for instance the Dell 1950 with 2x
Woodcrest 5160, 16GB of FB-Dimm memory, one 5i and one 5e perc raid
controller and some disks internally)
- An external SAS direct attached disks storage enclosure full with 15k
rpm 36GB disks (for instance the MD1000, with 15x 36GB 15k disks)
Going for the dell-solution would set you back "only" (including
savings) about $13-$14k. HP offers a similar solutions (a HP DL360G5 or
a DL380G5/DL385 with two MSA50's for instance) which also fit in your
budget afaik. The other players tend to be (a bit) more expensive, force
you to go with Fibre Channel or "ancient" SCSI external storage ;)
If you'd like to have a product by a generic vendor, have a look at the
Adaptec JS50 SAS Jbod enclosure or Promise's Vtrak 300 (both offer 12
sas/sata bays in 2U) for storage.
If you're limited to only 2U of rack space, its a bit more difficult to
get maximum I/O in your budget (you have basically space for about 8 or
12 3.5" disks (with generic suppliers) or 16 2.5" sff disks (with HP)).
But you should still be able to have two top-off-the-line x86 cpu's (amd
opteron 285 or intel woorcrest 5160) and 16GB of memory (even FB Dimm,
which is pretty expensive).
Best regards,
Arjen van der Meijden
On 8-8-2006 22:43, Kenji Morishige wrote:
I've asked for some help here a few months ago and got some really
helpfull
answers regarding RAID controllers and server configuration. Up until
recently I've been running PostgreSQL on a two year old Dual Xeon 3.06Ghz
machine with a single channel RAID controller (previously Adaptec 2200S,
but
now changed to LSI MegaRAID). The 2U unit is from a generic vendor using
what
I believe is a SuperMicro motherboard. In the last week after upgrading
the
RAID controller, the machine has had disk failure and some other issues.
I
would like to build a very reliable dedicated postgreSQL server that has
the
ultimate possible performance and reliabily for around $20,000. The
data set
size is only currently about 4GB, but is increasing by approximately 50MB
daily. The server also requires about 500 connections and I have been
monitoring about 100-200 queries per second at the moment. I am
planning to
run FreeBSD 6.1 if possible, but I am open to any other suggestions if it
improves performance.
I am considering a setup such as this:
- At least dual cpu (possibly with 2 cores each)
- 4GB of RAM
- 2 disk RAID 1 array for root disk
- 4 disk RAID 1+0 array for PGDATA
- 2 disk RAID 1 array for pg_xlog
Does anyone know a vendor that might be able provide such setup? Any
critique in this design? I'm thinking having a 2 channel RAID controller
to
seperate the PGDATA, root and pg_xlog.
Sincerely,
Kenji
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