Recommendations for server for web platforms.

[SkySpartan]

They asked me to make recommendations for a brand new server, to replace the current one. We use it to serve education platforms such as Moodle, Claroline, and a web conferencing software, OpenMeetings.
Right now we have 24 GB of RAM and a 1 TB magnetic hard disk that it is almost filled up. It has XenServer virtualization software on it, and those three systems will be migrated to the new one. The old one will be left as a development server for future releases of the aforementioned platforms.
We want the server to have SSD on it for faster access to the platforms, and have magnetic hard drives for less used data like backups, for example. I suppose hard drives for backups should be outside the server, but I don’t know how they handle backups, if we need another computer for the backups or the old server can be used for that purpose.
Also, lots of RAM is desirable, like 32 GB with expansion for more as needed. I’ve read that lots of CPU power is not needed in cases like these, or am I wrong?
Moodle and Claroline (I think OpenMeetings also) use databases to store their settings and some data, I don’t know how much they store on the database and outside them. So, I’ve read that if they use databases, the databases should be on another server, anything regarding that?, I’m not so sure about it, and use load balancers in front of the database and frontend server, another recommendation I’ve read.
I am a bit confused regarding the last part, any help and hardware configuration recommendations will be appreciated.

 

[dave_the_nerd]

They asked me to make recommendations for a brand new server, to replace the current one. We use it to serve education platforms such as Moodle, Claroline, and a web conferencing software, OpenMeetings.
Right now we have 24 GB of RAM and a 1 TB magnetic hard disk that it is almost filled up. It has XenServer virtualization software on it, and those three systems will be migrated to the new one. The old one will be left as a development server for future releases of the aforementioned platforms.
We want the server to have SSD on it for faster access to the platforms, and have magnetic hard drives for less used data like backups, for example. I suppose hard drives for backups should be outside the server, but I don’t know how they handle backups, if we need another computer for the backups or the old server can be used for that purpose.

If your backup server is literally only for data (say, the new server catches fire, so you restore the backups to the old server and fire that up, then order a replacement new server) then you can, no crap, just get a $200 NAS unit and dump copies of your XenServer virtual machine images to it every few hours. Cheap and easy.

You can get a lot more complicated than that if you want. Personally, if I had to homebrew something up in a garage with a box of scraps, I'd probably be doing some kind of block-level replication with DBRD. You'll need a second server for that, but it can be old, cheap, and slow; it just needs a NIC and some disks.

Also, lots of RAM is desirable, like 32 GB with expansion for more as needed. I’ve read that lots of CPU power is not needed in cases like these, or am I wrong

I'd try to go for 64GB now. My experience with school bureaucracy has been that it's usually harder to get funding for upgrades than it is to get a whole new server up front. If you're going to skimp anywhere, it's ok to skimp on CPU - none of the applications you mentioned are going to be very CPU intensive.

Moodle and Claroline (I think OpenMeetings also) use databases to store their settings and some data, I don’t know how much they store on the database and outside them. So, I’ve read that if they use databases, the databases should be on another server, anything regarding that?, I’m not so sure about it,

That's advanced class. If you're only dealing with a few dozen simultaneous users (small charter school or something) you don't need to bother - just install the database in the same VM as the application. Bonus points: when you back up the VM image, you back up EVERYTHING in one go. Very convenient.*

*I know, I know, crash consistency, blah blah. 99.9% of the time, nothing bad happens.

If your server is overloaded, moving the database application to another VM allows you to put the database on separate hardware for more speedz. (Or cluster your database across multiple systems for evem MOAR SPEEDZ.)

Here's the deal on that - if you're running on a single HDD right now, that's GOTTA be your bottleneck. You move this to SSDs, your new bottleneck will probably be RAM/CPU.

So IMO, you migrate over the existing VMs to the new hardware, fire 'em up, and see how you like the performance. If you like it, declare victory and find a Happy Hour. If you don't like it, look at three things - how much free RAM the Moodle (for instance) VM has, how much CPU is idle, and how much storage I/O is being used. (I would recommend running a synthetic benchmark likes the ones used in Ananadtech storage reviews, on the system first, so you know what your theoretical limit is.) If you're not maxing anything out, then you've got more performance capability than you're using, and the performance you have is what you get, unless you hire some ubernerds to re-engineer stuff. So you can once again declare victory and find a Happy Hour.

If something is capped, you can assign more CPU/RAM to a VM, and you can upgrade the RAM/CPU in the VM host if you have to, or oversubscribe it. But if you're running SSDs and your storage is still bottlenecked, then you're looking at serious $$$. Enough money that I'd be tempted to declare it "good enough anyway" and go find a Happy Hour.

and use load balancers in front of the database and frontend server, another recommendation I’ve read.

Well, for that to make sense, you'd have to be clustering multiple Moodle servers and/or multiple database servers. How many hundreds of thousands of clients do you have?

 

[SkySpartan]

If your backup server is literally only for data (say, the new server catches fire, so you restore the backups to the old server and fire that up, then order a replacement new server) then you can, no crap, just get a $200 NAS unit and dump copies of your XenServer virtual machine images to it every few hours. Cheap and easy.

You can get a lot more complicated than that if you want. Personally, if I had to homebrew something up in a garage with a box of scraps, I'd probably be doing some kind of block-level replication with DBRD. You'll need a second server for that, but it can be old, cheap, and slow; it just needs a NIC and some disks.



I'd try to go for 64GB now. My experience with school bureaucracy has been that it's usually harder to get funding for upgrades than it is to get a whole new server up front. If you're going to skimp anywhere, it's ok to skimp on CPU - none of the applications you mentioned are going to be very CPU intensive.



That's advanced class. If you're only dealing with a few dozen simultaneous users (small charter school or something) you don't need to bother - just install the database in the same VM as the application. Bonus points: when you back up the VM image, you back up EVERYTHING in one go. Very convenient.*

*I know, I know, crash consistency, blah blah. 99.9% of the time, nothing bad happens.

If your server is overloaded, moving the database application to another VM allows you to put the database on separate hardware for more speedz. (Or cluster your database across multiple systems for evem MOAR SPEEDZ.)

Here's the deal on that - if you're running on a single HDD right now, that's GOTTA be your bottleneck. You move this to SSDs, your new bottleneck will probably be RAM/CPU.

So IMO, you migrate over the existing VMs to the new hardware, fire 'em up, and see how you like the performance. If you like it, declare victory and find a Happy Hour. If you don't like it, look at three things - how much free RAM the Moodle (for instance) VM has, how much CPU is idle, and how much storage I/O is being used. (I would recommend running a synthetic benchmark likes the ones used in Ananadtech storage reviews, on the system first, so you know what your theoretical limit is.) If you're not maxing anything out, then you've got more performance capability than you're using, and the performance you have is what you get, unless you hire some ubernerds to re-engineer stuff. So you can once again declare victory and find a Happy Hour.

If something is capped, you can assign more CPU/RAM to a VM, and you can upgrade the RAM/CPU in the VM host if you have to, or oversubscribe it. But if you're running SSDs and your storage is still bottlenecked, then you're looking at serious $$$. Enough money that I'd be tempted to declare it "good enough anyway" and go find a Happy Hour.



Well, for that to make sense, you'd have to be clustering multiple Moodle servers and/or multiple database servers. How many hundreds of thousands of clients do you have?

Sorry for the late reply. At least for the time being, I think they will only pay for an upgrade, not a whole new server. So, I was thinking of buying hard drives (magnetic and SSD) from other brand (not HP that is the present server) because they are far cheaper than the original ones.
Now the server was down for 5 days, because one of the two hard drives went down (they are in RAID 1 mode) and they finally showed me the hard disk brand that it had. It is a Western Digital Enterprise class 1TB magnetic hard drive. So, I think that's no original hardware (I attach the photo):

(but it has HP serial left side)
Because of that, I think I can buy enterprise class hardware, but other brands, not exactly the ones from HP.
For example, I want to have 4 hard drives, 2 SSDs, 2 magnetic, each pair in RAID 1. So, the databases can be installed on the SSDs, and for the rest the magnetic drives.
That is possible with Xen Server?, have each virtual machine access the SSD and magnetic drive?. Thanks!.

 

[dave_the_nerd]

That is possible with Xen Server?, have each virtual machine access the SSD and magnetic drive?. Thanks!.

Yes. Not directly though - you have to create VM volumes either on the SSDs or on the HDDs and attach them to the VM you want.

Unless you do some kind of storage tier config with your RAID controller.

Non-HP branded drives should work fine, as long as they have the right connectors, but Enterprise-grade drives are probably a good idea.

You will probably need to buy some additional disk caddies/brackets/cables though. (Usually a few bucks each on eBay.) I highly recommend you get ones that are specifically designed by HP for use with your server, and don't try to improvise.

 

[SkySpartan]

I really thought that only HP parts would work lol
It is my first foray into server class hardware, so many doubts I had. I will talk with the people responsible for the server to make the upgrades and search for the parts asap. Thank you so much for the help!.

Yes. Not directly though - you have to create VM volumes either on the SSDs or on the HDDs and attach them to the VM you want.

Unless you do some kind of storage tier config with your RAID controller.

Non-HP branded drives should work fine, as long as they have the right connectors, but Enterprise-grade drives are probably a good idea.

You will probably need to buy some additional disk caddies/brackets/cables though. (Usually a few bucks each on eBay.) I highly recommend you get ones that are specifically designed by HP for use with your server, and don't try to improvise.

 

[sdifox]

exact model of server? Me think it's time for refresh.

also, backup sitting on the same machine is pointless.

 

[Carson Dyle]

Wow. Five days of downtime, on your lone server?

What's the context here? What's kind of company/organization? Apparently you own the server, and apparently your budget is pretty close to $0 if after five days of being down, someone isn't willing to pay for new hardware, just an upgrade. Is the server in colocation or is it sitting in the supply closet with a dsl connection to the world?