SAN in an Inverted Pyramid Architecture for Fourteen Physical Servers
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@Dashrender said:
So where is the savings with a $30K SAN? Not to mention the dedicated 1 Gb switch (actually at least two of them) if not 10 Gb switches or FC switches. oh and the adapters for that.
Well let's do some standard math and see where we fall. We have to make some assumptions, of course, but for the point of the scenario....
It is all about wasted capacity. How much is in each server? Let's say each has 6x 1TB drives in RAID 6. That's 4TB usable in each host. So 84 drives purchased with 56TB usable.
1/3rd of all drives are for parity. Performance is split up between 14 hosts.
Now how much capacity are we likely using? Chances are a huge percentage is wasted on each server. Typically we use less than half. Chances are we could get by with something like 20TB usable on RAID 6 on a single SAN. And the machines get to split the performance.
A single 24TB SAN might be cheaper than 84TB of raw storage across all boxes while still being just as flexible. That's where the potential cost savings come from and why SANs require a lot of physical hosts connected to them to begin to pay off - it is about getting to a scale where the drives become cheaper through a combination of thin provisioning, storage consolidation and better RAID overhead.
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Ok, that works if and when it's time to replace a huge percentage of that storage all at once, otherwise you're needing to spend a rather substantial CapEx and wasting the remaining life of the old but not obsolete equipment. I suppose you could sell it and recoup some of that expense, but assuming he keeps the servers and only sells the HD's, what kinda return can he really expect on those?
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@Dashrender said:
Ok, that works if and when it's time to replace a huge percentage of that storage all at once, otherwise you're needing to spend a rather substantial CapEx and wasting the remaining life of the old but not obsolete equipment.
The other choice is repeatedly investing in technical debt. It remains substantial CapEx in both cases, one is just lower and "at once" instead of larger and "spread out."
It's why good design before purchase is so important, the technical debt component that is often overlooked is often crippling.
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@scottalanmiller said:
@Dashrender said:
Ok, that works if and when it's time to replace a huge percentage of that storage all at once, otherwise you're needing to spend a rather substantial CapEx and wasting the remaining life of the old but not obsolete equipment.
The other choice is repeatedly investing in technical debt. It remains substantial CapEx in both cases, one is just lower and "at once" instead of larger and "spread out."
It's why good design before purchase is so important, the technical debt component that is often overlooked is often crippling.
Very true, but the organic growth of many business also makes this difficult at best.
You also didn't mention the network infrastructure and adapters needed to run the SAN in your cost analysis, but I'm sure you didn't forget them.
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@Dashrender said:
You also didn't mention the network infrastructure and adapters needed to run the SAN in your cost analysis, but I'm sure you didn't forget them.
For 14 hosts you typically have a lot of options and not very expensive ones. Lower end GigE switches will normally do the trick just fine. It is a relatively minor cost in most cases where we are not talking about extreme HA but just "SA" IPOD setups.
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@Dashrender said:
Very true, but the organic growth of many business also makes this difficult at best.
When you get to 14 physical servers you might be past the point of claiming organic growth planning
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Here is a little bit more information about the environment. Also, when it comes to budget, I have none. We are a 6 person shop mainly offering consulting services in the ERP arena to customers that have on premise infrastructure in place.
I have 14 physical servers, which I mentioned many are Hyper-V hosts. Not all of them are however. So here is a list:
Physical
1 - 7 are virtual host servers ( 84 virtual machines)
8. Dedicated backup server (in house stuff)
9. Dedicated backup (for client)
9. Dedicated SQL (for client)
10. Replica Server (in house)
11. Replica Server (for client)
12. Physical remote DC
13. Remote backup repository
14. Hot spare server - (parts).The VMs are virtual desktops, application servers for a couple clients, domain controllers, remote desktop services servers, and file servers)
Most of these are Dell R710s with a couple R620s and 1 R720 (mostly older stuff that was refreshed 3 or so years ago and was picked up refurbed) - all with internal storage and a mish mash of different raid controllers.
As mentioned above, we have been lucky so far and haven't had anything major break, because with the VM density on a couple hosts and the roles the VMs play would be a significant hit. Not to mention everything is out of warranty and there is no maintenance in place for the hardware. Does that make a good case for HA? It seems too.
Ideally, I would like to consolidate a lot of this, and undo some of the funky setup that exists. For instance, having a standalone server for the accounting data, (with it own domain, rds, virtual desktops) separate from the rest of the the network. For whatever reason, someone thought it was a good idea to just separate everything out by creating a new domain! We need a development , lets just create a new domain for that!
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@Carnival-Boy said:
@scottalanmiller said:
more reliable than an average server making the use of just one actually not much of a risk
When the SAN fails you lose access to ALL your business applications. Whereas if one of his servers fails he only loses access to 13/14 of his business applications (about 7%).
Not if you have replicated SANs.
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@Jason said:
@Carnival-Boy said:
@scottalanmiller said:
more reliable than an average server making the use of just one actually not much of a risk
When the SAN fails you lose access to ALL your business applications. Whereas if one of his servers fails he only loses access to 13/14 of his business applications (about 7%).
Not if you have replicated SANs.
The point here was (according to Scott) that the OP wouldn't have replicated SANs because they don't have a need for HA. They would be going to a SAN for cost savings reasons, little to nothing more.
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But before that conversation can really continue, the OP should have a DPack ran on his current setup and see if consolidation of his current workloads is possible, how much storage he can, if any, give up and then see if a SAN still makes sense?
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@Mfd201 said:
Here is a little bit more information about the environment. Also, when it comes to budget, I have none. We are a 6 person shop mainly offering consulting services in the ERP arena to customers that have on premise infrastructure in place.
I have 14 physical servers, which I mentioned many are Hyper-V hosts. Not all of them are however. So here is a list:
Physical
1 - 7 are virtual host servers ( 84 virtual machines)
8. Dedicated backup server (in house stuff)
9. Dedicated backup (for client)
9. Dedicated SQL (for client)
10. Replica Server (in house)
11. Replica Server (for client)
12. Physical remote DC
13. Remote backup repository
14. Hot spare server - (parts).The VMs are virtual desktops, application servers for a couple clients, domain controllers, remote desktop services servers, and file servers)
Most of these are Dell R710s with a couple R620s and 1 R720 (mostly older stuff that was refreshed 3 or so years ago and was picked up refurbed) - all with internal storage and a mish mash of different raid controllers.
As mentioned above, we have been lucky so far and haven't had anything major break, because with the VM density on a couple hosts and the roles the VMs play would be a significant hit. Not to mention everything is out of warranty and there is no maintenance in place for the hardware. Does that make a good case for HA? It seems too.
Ideally, I would like to consolidate a lot of this, and undo some of the funky setup that exists. For instance, having a standalone server for the accounting data, (with it own domain, rds, virtual desktops) separate from the rest of the the network. For whatever reason, someone thought it was a good idea to just separate everything out by creating a new domain! We need a development , lets just create a new domain for that!
Looking at consolidation may be a good idea. How much RAM and storage do you have in your 7 Hyper-V servers?
What about purchasing RAM for them ?
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The bad thing about splitting the threads is the purpose the OP originally had is lost to the new threads.
Scott reminded me that the OPs purpose was to find ways to grow his career, not specifically fix his current environment.
Of course that doesn't mean we can't help him do both
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@Dashrender said:
They would be going to a SAN for cost savings reasons, little to nothing more.
That is the only reason that you ever go to SAN. SAN is purely a cost savings measure at scale.
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@Dashrender said:
The bad thing about splitting the threads is the purpose the OP originally had is lost to the new threads.
Scott reminded me that the OPs purpose was to find ways to grow his career, not specifically fix his current environment.
Of course that doesn't mean we can't help him do both
Right, fixing the environment could be a great way to grow the career at the same time, which was my idea.
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@Dashrender said:
The bad thing about splitting the threads is the purpose the OP originally had is lost to the new threads.
And makes it likely that people start posting the new thread's stuff to both.
