Server replacement advice

[sidewinder]

As its almost new budget time we're looking to replace a few servers

 

first one is over 3 years old and out of warranty so would like to replace it as matter of course (although with 450GB of space id be loathed to get rid of it)

It currently acts as an apps server and also holds the common area

 

second one is only a few years old but has some reliability issues so Id prefer to move it to a less important role

It acts as a print server, Sophos server and RADIUS server. Stores IT Team data but that can go anywhere really

 

Instead of buying 2 new ones, which would cost a lot, I was thinking of maybe buying one very decent one with plenty of space for the Apps server, with enough power to run the Print, Sophos etc on a virtual server. Is this a good idea?

It would also give us back some valuable rack space

 

Is it advisable to run fairly essential services virtually and would there be much of a performance hit? Considering Id be thinking about maybe a dual CPU dual (or quad) core machine with 4/8GB RAM

 

Or if anyone has some completely different ideas Id be happy to hear them

[projector1]

we are in a very similar position

we need to address redundancy, storage and backing up. I have contacted a few ICT suppilers for consultancy. As they do this stuff all the time, we will get a better picture of what is the best way forward (major investment thus completelly analyse what is required to what is the common solutions being used)

They will come in and give us there reccommendations. We have a rough picture of what we want.

 

So my advice would to get some consultants in and see what they suggest, you do not have to buy what they say but it may make you look at the whole picture from a different angle

[localzuk]

I would be inclined to split the tasks still - you don't want to put too many tasks on a single server, loosing half your services is better than losing all of them if a server goes down.

 

A bit of info could be useful - What amount of storage are you going to need from the server(s)? Is the 450GB that you have now all being used?

 

How many applications, and what form of applications are being used on the storage server?

 

EDIT: Just some indications on the direction I would go. I would go for a couple of HP Proliant DL360 G5's - one with 6 HDD's and one with 2. And processors/memory according to their roles (file server doesn't need loads of processor power or huge amounts of memory, but if you want to run applications on it too, add accordingly).

[sidewinder]

True, but I was thinking about it from the perspective that the parts running on a virtual server could easily be transferred to another host server in case of emergency

 

We are not actually using all of the 450GB no, theres about 200GB free I think, and that covers all of our applications and common area

 

Applications used are varied, lots of software that simply sits there and runs straight from the network. A few that need server end software for licencing etc. And for storage of software that needs to be installed via GPO or locally. Probably not THAT resource intensive to be honest.

 

Not as if the server isnt coping, its a dual 3Ghz Xeon with 1GB RAM. It could do with more memory but probably alright apart from that.

 

I just feel as its out of warranty (so we could get no quick replacements of failed drives) and it is now the oldest server, it could do with replacing. Could also give it some other roles with the extra power

[localzuk]

Yeah, it sounds like the same situation for 2 of our servers - and we have 2 of the HP proliant dl360 g5's with 2 146Gb SAS drives, dual 5150 processors and 2GB RAM each (could add some more in a year or so). I also have a Snap Server 520 with 2TB of storage which is connected via iSCSI in a very primitive SAN setup (over ethernet).

 

This is a little overkill for your storage needs probably, you could use the extra 4 drive bays in one of the machines and make up the space you need that way.

[john]

I will agree with the HP Proliants, I have used the ML370 G5 and that is great, so I'm sure the DL is just as good as they have been in the past.

[m25man]

localzuk has the right idea.

 

School networks have outgrown the old concept of Server + Raid Array = Good Network.

 

With more and more users wanting to access more and more "different" services and a tenfold increase in user data storage requirements entry level SAN's are the way to go.

 

iSCSI has already forced a massive reduction in pricing, the newer HP Switches support iSCSI out of the box, Host adapters are cheap and Server 2003 R2 has iSCSI support out of the box.

 

Now re-assigning a disk volume located on a SAN can be re-assigned to another server on demand.

Volumes can be duplicated expanded, assigned, re-allocated clustering is easier than ever.

 

There are entry level systems coming on-line at less than 10k

 

There will be winners and loosers, early adopters will pay a higher price but will master the technology earlier. Those that hold out will benefit from the cost cutting that will occur as result of higher demand.

[Geoff]

Don't forget you can DIY an iSCSI SAN with Linux too. Might be a good entry level option to prove the concept to the SMT.

[srochford]

DIY is certainly an attractive option. 10k might not sound like much to some schools but to me (in FE) it's an awful lot of money - equivalent to about 6 standard servers!

 

I know it's "the future" and makes sense but we're looking for ways we can cut spending and SANs don't look like helping just yet.

[tom_newton]

Re: virtualisation, I see it as a good way to turn 3 servers into 2 - I don't like turning 2 into 1 as you do lose some resilience. Also, if you are going to virtualise, I would look at 2 VMs over VMWare enterprise or similar, so you dont have to worry so much about periphery on the "Host" OS and you get virtualisation type benefits (ease of moving etc.) for both servers.

[Geoff]

It's also required for something like our Citrix servers. We're buying big boxes with 8Gb of ram in them but 32bit windows can only see 4Gb. So we'll have to run a 64bit Host OS and virtualise the machines into 2 or more virtual servers.

[m25man]

10k might not sound like much to some schools but to me (in FE) it's an awful lot of money - equivalent to about 6 standard servers!

 

But what versatility, need to add extra storage to an existing server put a HBA in it and your away, you can even boot from it!

 

Loads of 1u Blades all plugged into a massive SAN Bliss!

 

Just to P**s you of a school down the road from you "Found" 20k left over in the IT budget at the end of the year and gave the IT manager about 3 hrs to spend it. needless to say without proper time to plan the spend wisely they spent more than half of it on crap!

 

At the other end of the scale most state schools would have spent 10K in the first few weeks on supply teachers so the IT budget get squeezed to counter for somebody elses bad management.

 

I see it all, and in most cases to the victor goes the spoils.

School Network Managers tend to be yes men happy to take whatever scraps they are given.

 

There are a few who have excellent negotiation skills and secure a fair slice of the cake when it comes to budget time.

 

Be adventurous write a business plan sell it to the SMT and push for as much as you can get away with, that way a 10K SAN could end up being just the cherry on the cake!

[DMcCoy]

My SAN alone cost £20k

 

I am running a large amount of server based applications though, I had 5 servers to replace, and was at least another 4 short.

 

I then spent £80k (leased for 3 years - 4th year+ is much cheaper )

 

Sounds a lot of money and it is. I did however replace the entire server structure in one go. This included tape library, SAN, Fibre channel switches, ESX software (its actually a lot cheaper now), gold support, cabinet, ups, backup software, backup server. I have a blade center with 6 blades running with 20+ VMs with room for another 15 or so, depending on use. Additional power was installed and Air conditioning.

 

I'm sure some people out there are fainting at the cost, but don't forget this was the entire server infrastructure in one go, as little had been spent on servers for quite a long time.

 

The replacements (not for a while yet) will be much cheaper (SAN prices have come down, same for ESX), and what do I have to do to move all the servers? Copy the images to a NAS, install the ESX hosts, copy the images to whatever new storage system is used and power them up. Can be done in 2-3 days if the testing has been done on the new system.

[m25man]

My SAN alone cost £20k

 

I have a blade center with 6 blades running with 20+ VMs with room for another 15 or so, depending on use.

 

What spec blades are you using to host 20+ VMs ?

 

And how are they weighted?

Eg

Blade 1 = DC1 100%

Blade 2 = DC2, AV, Media @33,33,33

Blade 3 = DNS, RIS, Radius @33,33,33

Blade 4 = SQL1, SQL2, Linux Sandbox, Internet Filtering @35,25,15,25

 

I have found it hard to run any more than 2 or 3 VS2005's on a single Xeon but running on Quads, VS is as good as a real server and I have had 8 VM's running on a single quad core.

 

How do you do it? Any suggestions for this years Datacenter Deployments in our secondary schools or are we just going to roll over and have RM put a couple of CC4 boxes in uner a BSF contract for the next 10 years. 8O

[robknowles]

Hello,

 

I definitely recommend going to Virtual Machines for some tasks (though I personally would leave ISA Boxes, SQL Servers and Domain Controllers as physical servers). I've just put a server in here - a 2 x Quad 2.33GHz, with 8GB Ram and 2 x 73GB SAS HDD - 15K RPM that are Raid 1 to host the ESX Server and Swap Partition etc, and 4 x 300GB HDD SAS 15K RPM - RAID 10 to host the Virtual Machine Images. Performance is excellent - I'm amazed how little usage is made barely 2GHz is reached and that's running about 8 Virtual Machines, of which my Sophos Server and Printer Server is part of. I've noticed no performance issues since Virtualising these.

 

What I'm looking at doing this year (budget dependent) is to upgrade the higher version of VMWare ESX Server and install an additional 8GB Ram, and then purchase an additional server to run VMWare ESX as a replacement for a couple of older ones. I'm also looking at buying a iSCSI SAN so I can host the VM Images on this and in case one server fails the VMWare ESX Server will simply transfer the VM Machines that were running on the failed one and then continue on the new one.

 

Rob

[sidewinder]

Im liking the idea of an iSCSI SAN

Should be fairly easy to convince SMT as it should reduce costs in the long term as we would have to buy less expensive replacement servers and could just upgrade the SAN each year

 

Few basic (probably ignorant) questions. I did have a search but couldnt find any definative answers:

 

1. For iSCSI, would it be set up as follows:

Each server has one NIC connected to internal network, and one connected to another switch thats connected to the SAN? Drives are then mapped to each server and appear as local drives

Thats how I understand it but I could well be wrong

 

2. When you want to add an extra disk, can you just drop it in and your capacity increases just like that?

 

3. Is there any redundancy if a disk fails? This is the bit that confuses me the most because it doesnt seem to be mentioned anywhere. Is there any sort of RAID built in? Or would you have to replace the disk and restore everything from backup?

[robknowles]

1) Yes that's correct. You could to save cash connect to SAN Unit to your main core switch, but I would recommended purchasing a seperate switch as you suggested and connecting the servers and san to it (that's how I will be doing it). You will use the iSCSI software (probably the Windows one) to attach the drive letter to a iSCSI Target

 

2) The iSCSI device will have management software and then you can add the disk and then configure the system and then if increase the size for the different 'disks'

 

3) On the device you can setup RAID 5, and most should support RAID 10/50 etc. You should be able to setup a Hotswap Spare as well.

 

Rob

[DMcCoy]

A few words of caution, if you want to use ESX, then your hardware *MUST* be on the ESX hardware compatability list.

 

While it uses a linux VM to manage the host, the ESX kernel itself is custom, if it's not on the list, you cannot add drivers for the device.

 

I'm using 6 Dell 1855 blades with Dual Xeons 3.0 with 4GB ram. They have been in production use for around 18 months, and were bought 2 year ago. I run minimal services on each VM so that I can reboot them without affecting too much of the network at a time.

 

I had to get a Fibre Channel SAN as at the time ESX did not support iSCSI, one of the reasons for the high price.

 

ESX is very different from the MS and other VMware products that sit on an OS. It doesn't use SAN agent software for example and has connects itself.

 

I've not done too much arranging of the VMs on the physical servers at the moment as if I find any that pull too many resources I vmotion them to another blade (one of the joys of ESX using a SAN is hot migration to another physical host of VMs).

 

ESX is not for the faint of heart and it requires a lot of detailed knowledge of SANs, Fibre switches, vlans and trunking. I've managed to learn what I need to know, but it has been a bit complicated at times

 

The only current issue I have is that I cannot host 64 bit VMs, as my processors are too early a revision and don't support intels VT extensions. I will live without a virtual exchange 2007 for now (although I am on 2003).

[sidewinder]

Have just been thinking about performance with an iSCSI SAN

 

At the minute all data is stored on servers local disks, all at least 10K SCSI ones.

A SAN (at least the Dell one ive been looking at) has only 7,200RPM disks. Plus then theres a small overhead I assume when the drives are mapped to a server.

Also, although it would have its own dedicated switch, surely 4/5 servers all accessing the data through 1 1GB connection would be slower than it is now?

[localzuk]

You can get san devices with whatever hard disks you want in them - so 15k SAS drives are possible if you are willing to pay for it.

 

Remember that Hard Disk access is the slowest part of any computer, so a 1GB network connection shouldn't be a bottleneck for any normal school usage (our main file server which uses our iSCSI device only works up a sweat of ~10Mbits per second during normal hours, and 50Mbits per second when it is doing a full system backup. That is barely using the 1Gb connection really (that is with usually 70 people accessing stuff on there at the same time, scale up accordingly).

[zag]

Surprised at the level of servers required in some schools, we still use basic servers with cheap big hard disks and simple hardware configurations. Creating a 1tb array is cheap these days and can be reliable. I saw an interesting article somewhere about how Google do this instead of buying expensive custom Storage solutions.

 

One thing I wouldn't use is Raid for the system drive as I have had a number of problems with OS corruption over the years.

 

SANs are definitely the way forward but I still think the cost benefit is not quitet there yet.

[localzuk]

@ittech - Schools are supposed to be moving towards a reliable/robust system similar to those used in business. This should be done through reliable hardware and using industry standard technologies such as RAID/SANs etc... Take a look at the Becta website for information about what schools should be doing now.

 

Google have created their own OS to provide distributed storage resiliance, so have spent a huge amount of money on developing this.

 

Using a quick and cheap home built solution can be reliable but if it isn't, it is your arse on the line.

 

Also, you should use RAID for the system drive, just use hardware raid in a mirrored fashion - if you don't use it, you simply add a large 'reinstall' time when the main disc does fail, and add a possibility of data loss due to backups not being completely in sync with the data on the drive.

[sidewinder]

Taking my time over the SAN so no rush for that

 

But I do need to order a print server quite soon

 

The one I was going to get was a Dell Poweredge 1950 (went with as many energy smart options as possible, need to try and make a bit of an effort)

 

Specs:

2x Dual Core Xeon 5148LV 2.33Ghz

4GB RAM

2 73GB 10,000RPM 2.5" SAS Hard Drives in RAID 1

1U Chassis

 

Would be running, as well as printers, Sophos, QCA Testing and Certificate Services

 

2 things:

 

a) Would a 1U chassis cause a lot more noise/heat? Because it would be extremely useful space wise

 

b) Would it be sensible to get a 3rd hard disk just to use as a separate volume? As far as I can remember none of those applications recommend data on a seperate volume to the OS

[Geoff]

Would a 1U chassis cause a lot more noise/heat? Because it would be extremely useful space wise

 

It only becomes an issue when you have an entire rack of them. Twice the heat/power/etc vs 2u servers.

 

Would it be sensible to get a 3rd hard disk just to use as a separate volume? As far as I can remember none of those applications recommend data on a seperate volume to the OS

 

Well, when you get your SAN running this kind of stuff will live there. So with that in mind, I'd just leave the drives set as mirrored raid. If you partition the raid up into two volumes this'll make it easy to migrate your data to the SAN later on though. If you prefer to use a 2nd hard drive, I don't see why that wouldn't work to.

[sidewinder]

Very true, its hard to get out of the habit of thinking of local storage all the time!

 

Thanks