On Fri, 09 Jan 2004 04:59:46 +0100, Jens Frank wrote:
* single host reliability can be "low" if
the farm is available, so high end
features are not required.
+5 ;-)
An interesting links on Google's hardware strategy:
http://www.pcworld.com/resource/printable/article/0,aid,112891,00.asp
A quote:
Google's infrastructure: Google uses consumer-level hard disks and
'really cheap, unreliable memory.' ('If something fails, it's not
you, it's probably the memory.') They have around 10,000
commodity-level Linux computers set up in a parallel network ('the
largest Linux cluster in the world'), and anticipate the death of 'a
few machines every day.' Their network is set up to be able to route
around a failed machine instantly.
* Many similar boxes provide higher flexibility than
many different boxes.
To me this doesn't make that much sense- why spend a fair amount of extra
money on the idea of having flexibility with machines capable of doing
other tasks? If we save some money now by buying cheap yet more powerful
(more of them) Apaches we're extremely flexible to spend the remaining
money on whatever becomes necessary. And which major changes are
anticipated?
= Configuration =
The question is whether to use 4 of the "squid-class" single CPU servers
or two of the "DB Backup class" dual opterons. 4 of the small boxes would
cost 7,240$. Two of the big servers would be at 5,620$.
Both options are are a misfit for the Apaches.
* they have practically no disk access- no logging, no swapping, no data
stored on the Apaches. Only disk access on boot and when scaling
images. Hence no raid, smallest/cheapest hd available.
* 'Low' reliability is ok, many machines
So time for some numbers.
== Apache ==
If we really wanted to go for
as-much-performance-for-the-money-as-we-can-get and there was space for
regular tower pcs in the colo:
Dell PowerEdge 600SC
Intel® Pentium®4 Processor at 2.4GHz
512MB DDR, SDRAM 2x256
40GB 7.2K RPM IDE Hard Drive
$797,-
otherwise rackmount 1U:
Dell PowerEdge 650
Intel Pentium 4, 2.4GHz, 512K, 533MHz, with Floppy /CDROM
1.0GB DDR,266MHZ,2X512MB DIMM
Price:$1,098.00
So it depends:
6 * PowerEdge 600SC = $4,782.00 (tower)
6 * PowerEdge 650 = $6,588.00 (rack 1U)
== Squids ==
Dell's pricing for 4Gigs ram is pretty bad:
PowerEdge 1750
Intel Xeon 2.4GHz w/512K Cache
4GB DDR,266MHz,4X1GB DIMMS
On-Board RAID 1, PERC4-DI, 128MB Battery Backed Cache, 1 Int 1 ext Ch-Embedded Raid
2 x 36GB,10K RPM, 1in (Ultra 320) SCSI Hot Plug Hard Drive
Price: $3,516.00
Better, but only 3 Gigs:
PowerEdge 650, Intel Pentium 4, 2.4GHz,
3.0GB DDR,266MHZ,3X1GB DIMM
2x 80Gb IDE RAID1
$2,885.00
The xeon isn't necessary, but 4 gigs on smaller cpus works out at the same
price at dell. So no business for dell here ;-)
I'm unshure about the opteron (Dell only lists Intel- a dual Xeon
2.4Ghz with 4Gigs and 2x 73GB 10K RPM Ultra 320 SCSI RAID1 would cost
$4,545.00).
So, cheap version (towers for Apaches), 6 instead of 4 P4s:
6 Apaches P4, 512Mb- 4,782$
1 Dual Xeon DB 4Gb - 4,545$
2 Squids P4, 3Gb - 5,770$
-----------------------------
15097$
-1000$ disc. 14097$
all rackmount:
6 Apaches P4, 1Gb - 6,588$ (Dell)
else same as above
------------------------------
16,903$
-400$ disc. 16,503$
This doen't include Fileservers, it should be possible to use the DB
machines for this (or the old machines, if we don't want to use them as
spares).
Note that both options would buy significantly more power than Jens'
proposal.
2 Gigs for the Squids is something i'd really like to avoid, 3 Gigs might
be a compromise. The 4 Gig machines seem to be very expensive.
I'm not shure if it makes sense to use a dual Xeon for the DB- i'm
no expert there. The server has 6 ram slots, with four taken in this
config. Maximum ram possible is 12Gb.
--
Gabriel Wicke
