Web Hosting Talk : Web Hosting Main Forums : Dedicated Server : Advice Required

[SmileServe]

Hi,

1. I'm considering ordering a server which has 16GB of RAM. To take advantage of this I would need an x64 OS. Now in the past cPanel and x64 operating systems didn't seem to work very well (from personal experience and other peoples). However this was a few years ago. I've been told by my server management company that using CentOS 5.x x64 should be perfectly fine with cPanel. Does anyone have any thoughts regarding this?

2. I am considering combining several lower spec servers into one "mega" server. Basically spec-wise the new server should be able to easily "absorb" the server loads from the other servers combined and then some...
My server management company tends to think this is a bad idea mainly due to issues such as "putting all my eggs in one basket" and making my company seem larger if I have more servers. However we are talking about $450+ savings per month and easier management of users etc if we go with this new plan. So basically I'm not entirely sure if $450+ per month is worth avoiding minor issues which are not likely to happen often if ever. Has anyone else had any experience with doing this? The bottom line is that the facts and figures spec wise all add up but there's just a few questionable issues...
Also worth noting is that the server management company in question will end up with $200 less from me every month if this plan goes through so that may have had a bearing on their opinion...

3. Are 15K SCSI drives much better than 10K ones? From reading around and the server management companies advice they certainly are worth getting versus 10K.

Just want a few independant opinions on these issues...thanks.

[GPearce]

Thats some serious power
X64 and cPanel never gave me any problems before, as long as the OS supports it, you should be fine.

2. - Clustering would be a good approach to doing somehign like that , and then you can have them in seperate locations, also removing the risk of downtime if one dc goes down

Hope that helped

[uberjon]

i have heard of people having "issues" with 64 bit centos 5 and cpanel. although i have heard none for centos 4 64 bit.

i was going to choose 5 but i was recommended not to.

although i only got 4gb of ram.

i think it would be better off having a single system than multiple to make one system..


its like adding 3 hard drives to your pc and raid 0 them with your current hd.

each hard drive you add increases the risk one will fail. (and if one fails they all fail)

not sure if a cluster can sustain failure of one whole machine. or parts of multiple machines or not....

but it just sounds so complicated... and usually most simple method is better.....

as for the hard drives...

what do you plan on doing with them?

like a few in raid 1/5/10 for main drive. then a few large in raid 1 for backup or like 6-8 of them in raid 10 for the entire thing?

and budget? (personally id just go with raptors....)

as my debate in the other thread about raptors vs 15k sas drives....

for the price of 2 15k sas drives. you can get like 5.5 150gb raptors..... so round that up to 6.

raid 1 the sas drives. (mirror = no gain in performance really. just redundancy..)

raid 10 the 6 raptors. (3 for mirror 3 for stripe)
you get redundancy just like the sas. but you get the benefit of the stripe as well.

(1v1 the sas will win.)

but if you compare prices. when you can get like 3 raptors for price of one sas 15k..... there is no point in it really. you would be better off with the raptor.

[GPearce]

CentOS4 is meant ot be better for cPanel, and im not sure about the drives.. WHen i have the choice and the money, i go for the best RAID i can, in the hope that it will give the best reliabliliby.
16gb of RAM still seems a lot for me

[SmileServe]

Thanks very much guys!

Clustering - I'm not looking to go this route but it's a good relevant suggestion anyhow so thanks for that.

Raptor drives - If it wasn't for the fact they are rather small and this particular server can only hold 3 drives then yes I'd look into this. But that pretty much rules it out...

Raid - we used to use RAID setups but it seemed to actually attract problems which wouldn't happen otherwise! We feel that a really top-notch and multi-layered backup system works great.

[GPearce]

Sounds fair enough. Raptor drives are too small to use for hosting really, and in domain serving, they dont make enough difference to make the additional cost worthwhile. Go for WD 7300 rpm ones and you should be fine

[huck]

Well, to me you have two completely different issues here.

The first is the "putting all of your eggs in one basket" issue.

The second is a technical one about CentOS 5/64Bit and Cpanel. I assume you are stuck with cPanel? We've seen various issues with Panel on 64bit issues. Some related to PHP/Apache, but most can be overcome. I've no specific experience with CentOS 5 and cPanel.


The first issue is not as much a server management questions as it is a business question. When we are asked about this issue we ask clients to ask a few questions about their operations. Every hosting provider has different practices, SLAs and other quirks that makes each case unique.

For example, say you have 4 servers and your accounts evenly balanced over the server. When I say evenly balanced I mean from a revenue standpoint not a technical one. If your revenues are split equally over 4 servers and if one fails, then only 25% of your revenues are at risk of loss. If all of your sites were on a single server, then 100% of your revenues would be at risk of loss.

Now here's the hard part. If you were to have a server outage, what type of cancellation rate would you have? This is a very important question. Say you've understanding clients and if you had a server failure, they would be sympathetic if a 4-8 hour outage occurred. Maybe only 2% would cancel. In this case, you could save a lot of money through consolidation. You may decided to give up part of that savings and put in place very robust backups and use a datacenter that can quickly restore hardware.

You can look at this like you would insurance. Let's say that the total savings of consolidation are $450/month in direct savings and another $150.00/month in productivity. So you are spending $7200/year to reduce your risk exposure by a factor of 4. Is this worth it? Only you can answer that based on your business model and finances.

Another way to look at this is how many customers would have to cancel to lose $7200/yr in revenue?

I hope this helps. Too often I see people let technical decisions guide business decisions and not the other way around. Imagine if you had another $7200 to spend for marketing? On the other hand, imagine if your server failed and was down for 24 hours. how much business would you lose?

[luki]

Do you really need 64-bit architecture to take advantage of 16 GB of RAM? I know that you need it if you want more than 3 GB per process, but if you don't need that then a 32-bit kernel with HighMem support should work:

CONFIG_HIGHMEM64G:
Select this if you have a 32-bit processor and more than 4 gigabytes of physical RAM.

[SmileServe]

huck - Thank you very much! Your post was one of the most informative and logical thinking posts I have read in ages! Honestly, it has helped me a lot.

luki - This is interesting. However judging from the consensus over various people I've asked and server management company 64bit is the way to go. If you had asked me a few years ago I would have given a definite no, however things have changed, a lot. Also with this consolidation every extra bit of added performance is very much worth it. BTW - I like your sig...lol.

[huck]

Just an FYI: We typically deploy 32bit systems unless there is a compelling need for the 64bit, such as high database activity. MySQL has some gains on 64bit. I don't think Apache 1.3, which cPanel, uses would make much difference. I also doubt the performance will be noticeable. We are talking small percentages here. The difference in 10K vs 15K disk drives would be much greater than 32 vs. 64 bit.

I would save yourself the headache and go with 32bit systems. The fractional % in performance you will eek out may not be worth the problems it can bring when using cPanel.

[SmileServe]

Yes , it seems some people are telling me 64bit is fine with cPanel whereas others are not.

However the RAM issue...how well is 16GB of RAM going to work with a 32bit build using CONFIG_HIGHMEM64G versus a 64bit build?

[luki]

Sorry, I cannot comment how well 16 GB would work with a 32-bit architecture (the kernel note says up to 64 GB is supported). The performance difference due to 32 vs. 64 bits highly depends on the package. I once did a comparison on an Opteron 285 with 4 GB RAM using our modeling package on the same identical hardware, and the gain was 3% on the 64-bit platform. This molecular modeling package is purely CPU bound with a run taking about an hour, so you save couple minutes. Since we run it on 132 cluster nodes 24x7, the gain was worthwhile for us. No problems with 64-bit (Fedora 4 x86_64). YMMV.