On Thu, Jan 08, 2004 at 04:37:58AM -0800, Jimmy Wales wrote:
Jens Frank wrote:
1 CPU at about 2GHz 2 GB RAM 2*36G 15kRPM SCSI Disks Remote controller (rILO, eRIC) for remote "lights out" management 1 Unit rack mountable redundant power supply
Being most familiar with Compaq's Intel servers, I configured the box in their webshop and it was about 4,000$
I just looked at a configuration at Silicon Mechanics. (But, I am also considering another vendor with similar prices, Penguin Computing. And I'm open to more suggestions, as always.)
SM-1151SATA, http://www.siliconmechanics.com/i1511/p4-server.php
1 CPU at 2.4GHZ P4. (They offer a cheaper Celeron, I'm not sure if the P4 is worth the extra money for webserving or not.)
The 2,6 GHz is 1$ cheaper. If you want to buy the same boxes for all purpose (squid+apache), I'd go for the faster CPU.
2 GB Ram (2x1GB, which is a little more expensive than 4x512, but leaves slots open for future growth.)
The SM-1151SATA has non-ECC memory. Being used to ECC and even hot spare memory, I'm not comfortable with this. 2*1GB is what I'd use, too.
2*80G 7.2kRPM, 8MB cache SATA drives
SATA RAID controller (we could run raid 0 or 1 for redundancy or speed - since a webserver ought not hit the disk all that much, I think redundancy is more important)
Looking at pliny and larousse, from the numbers I've been told, their disks are highly busy, bi and bo are very high in vmstat.
NO CD-ROM yes floppy Red Hat 9
The price on this box is $1951. Going with a cheaper processor, and (4x512) RAM, I can get that down to $1579.
Comparing with the above compaq it looks cheap. It has no ECC, no remote management, no redundant power supply, no 15kRPM disks, though.
Remote management cards are really useful coping with crashed servers. It starts with being able to read the kernel panic message, being able to power off and on the server, and advanced ones being even able to insert a "virtual floppy" during booting (Remember the crash we had while trying to remotely update the kernel?). http://www.techland.co.uk/index/eric is a vendor-independent RMB. Compaq's ILO-boards are much more powerfull, though.
SATA vs. SCSI -- SCSI is theoretically faster, although many say that the practical difference is minimal. SCSI is theoretically more reliable, but with 2 SATA drives in RAID redundant configuration, this is a very minor issue?
There probably isn't much difference between a SCSI and a SATA interface for the same disk. The difference is mainly in the disk seek time since SCSI disks are available at 15kRPM, while SATA are mostly 7,2kRPM.
Anyhow, for reference, the same exact configurations as above, but with SCSI instead of SATA (and only 36Gb disks instead of 80Gb since disk size on the webserver boxes is not so important):
$2521/$1749.
Just for clarity in case people dozed off during the boring bits above:
SATA 80GB RAID $1951 or $1579 depending on ram/processor SCSI 36GB RAID $2521 or $1749 depending on ram/processor
Strange that the difference is 600$ for one configuration and 170$ for the other. Thinking of Squid, I'd rather spend the money for 2 Gigs of additional memory than for the faster disks. Memory should dramatically reduce I/O load on proxies. 2 additional GB are 762$.
I am thinking of buying several of these boxes, to be potentially used in these capacities:
load balancers (2) squid proxies (3) web servers (4) backup db machine (1) (this one should be stuffed with extra ram and the fastest processor, I guess)
Many alternative configurations are possible, esp. if as the current trend seems to suggest, we eliminate the load balancers and simply count on squid+heartbeat
You'd need heartbeat for the load balancers, anyway. Doing it on the squids would just save two boxes.
Why three squids? Two would be enough, and even one should be able to handle the load if the other one fails.
Should the DB backup machine really have a different sizing from the active machine? From what I've seen brion say geoffrin is rather idle, so perhaps yes. On the other hand side, administration would be easier when having two identical boxes, or at least same CPU family. A small Altus 1000 E dual Opteron (single Opterons are not offered by penguincomputing?) with 2 GB RAM (ECC!), 2*80 disk, no CDROM, is at 2,810 $. We could probably get away with two of these for web serving instead of four, and save 2 units of rackspace.
2 squids, single CPU (Relion 1X, 2GB, 2,66 GHz P4, 2*80 GB) 2x 2,150$ 2 webservers, dual Opteron (Altus 1000E, 2GB, 2*Opteron 240 2*80GB) 2x 2,810$ 1 DB Backup box (same) 1x 2,810$ ========= Total 12,730$
Using 4 webservers at $1951 each would cost 2,184$ more, plus 2RU space consumption.
then we would have database machine as geoffrin, the big dog, when fixed and other old hardware eventually moved to the new colo to be mailserver, etc.
Our budget is $20,000 but we have more money than that by far, donated by people who knew that we were already over $20,000. We don't want to go crazy and spend it because we have it -- better to take a wait and see attitude, because hardware will only get cheaper, and our needs will be better understoood in a few months. However, going a little bit over or under should be no cause for concern, if the purpose is valid.
Very good point.
Regards,
JeLuF
PS: Sorry if this became to long.