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SAN Solution- what the heck am I looking for??
February 5, 2013 11:40 AM   Subscribe

What options and features or solutions should we be looking for in a SAN solution that will need to last 7-10 years.

We're looking to virtualize (VMware of Hyper V, not sure which yet) our old servers this summer and hosting the VMs on a SAN, along with transitioning all of our user Homes & Shares to the SAN. I've been talking to a few companies and realized a small problem: I have no idea what to even ask or which features I should be looking for in a reliable SAN, or options that 3 years from now I'll be kicking myself for not looking at now. Or recommandations for solutions to look at myself on the side. Of course, all the companies say *their* solution is Epic, but I've learned to be skeptical and I am not partial to any one company.

Basically, we'll have about 10 servers (mix of OSX, Windows Linux) feeding off the SAN with about 500 users (95% OSX, 5% Windows- their home folders all use a Mac Pro Server, which is rapidly running out of space. *sigh* Xsan).

Of course, cost is a concern, but I've also convinced TPTB that based off our experience in IT purchasing, choosing a solution that maybe costs some extra money now is worth the cost of eliminating headaches due to choosing an inferior product today.
posted by jmd82 to Computers & Internet (12 answers total) 1 user marked this as a favorite
 
Do you understand the difference between SAN and NAS? Because, typically, things like Home directories and Shares are stored on a NAS, not a SAN. It's also possible to host VMs on a NAS, and that MIGHT be the right solution for you, in that it's easier to understand, easier to engineer, has much less equipment to buy, and gives you a easier migration path in the future.
posted by 1970s Antihero at 12:27 PM on February 5, 2013


The plan is to connect the SAN to our Mac Server as virtual space and allocate more space that way.
posted by jmd82 at 12:44 PM on February 5, 2013


I'm confused as to what you are trying to do. First you mention VMWare and running VMs on a SAN, then you want to "connect the SAN" to a "Mac Server". I have no experience with the latter but we run an array of Dell Servers with vsphere 5 and a DELL Equalogic PS6110xs (iSCSI 10Gb, mix of SAS and SSDs with intelligent tiering). The servers run on ESXi 5 and each host about 10-15 virtual servers (Linux and Windows 2008). The SAN is only exposed to the guest OS by virtual disks which allows us to migrate virtual machines on the fly from host to host and provides fault tolerance. If a vm host fails we just restart the virtual machine on another host. With VMWare HA you can even automate the fault tolerance to a certain degree, given enough host resources.
Some questions:
1) Do you need fault tolerance, and if so to what degree? (You would have to implement redundant SAN nodes or even virtualize the SAN with something like DataCore)
2) What's the work load? Are we talking about file servers or something more CPU intensive? What about expected I/O workloads? Database servers?
3) Do you expect the number of servers to grow rapidly?
4) What's you budget? Our setup with 3 hosts and the EQL is in the range of $70k. Don't forget you need a complete set of infrastructure hardware (redundant fibre channel or 10Gb iSCSI switches, network adapters, cabling..) plus licences
5) 10 years seems a bit unrealistic. At some point replacement drives and other parts will make maintaining the SAN an economic nightmare. We dropped EMC for that reason.

You should really talk to some storage experts at HP and DELL, they'll be more than happy to ask the right questions and come up with ideas.
posted by Nightwind at 1:10 PM on February 5, 2013


Ask this question over there, and you'll likely get some good responses.

If it's really just home folder storage and light VM duty, you're looking for a glorified NAS. Synology, whose two-to-four bay products I find reasonably good, now have some higher end kit that will do high availability and SSD caching, so can handle moderate workloads. Some of their stuff is VMWare certified, which is nice.
posted by wierdo at 1:14 PM on February 5, 2013


Do any of the (future) VMs need high availability features? Fault tolerance? What are your current space requirements for the VMs? Your shares and other data? What kind of domain infrastructure are you running? (I'm assuming OD.) Are you hosting email internally? What are your future projections for data usage 7-10 years down the line? (The last part can be really difficult to answer, obviously.) Do you want or need to balance out VM usage loads in real time across your virtual cluster? (In which case you might want to consider a VMWare license that supports vMotion.)

How much are you willing to spend? You can get a few physical hosts to run all of the VMs, something like an HP P4300 to present storage to the hosts, and a handful of switches to connect them relatively cheaply. Or you can go nuts and buy something bigger from a vendor like EMC or NetApp and present that to whatever hosts are running the VMs. I have more experience with expensive stuff from these two vendors.

How much time are you willing to spend babysitting all of this stuff? Configuring it and getting it running? P-to-Ving the physical servers? These are also questions you should be asking, as there's a not insignificant amount of labor involved in virtualizing your environment.

I'm not too familiar with open source storage options such as OpenFiler, and can't vouch for it. However, on preview, something cheaper might suit you if you're just emphasizing having more space for user directories. You'll probably quickly outgrow something smaller like a ReadyNAS, although presenting that to a Mac server seems fairly straightforward.
posted by peeet at 1:14 PM on February 5, 2013


I am looking for fault tolerance. We've had issues with not having high-availability in the past, and definitely trying to avoid that. Our biggest servers are for for Student Information System (pretty CPU intensive as teachers are constantly tapping it), financial software, and will be implementing some kind of Moodle setup over the summer. A few other things like Web filter database, AV, etc., that get used, but not high-priority for end-user speed. Our server utilization shouldn't increase too much over the next few years, but I also don't want to be hamstrung but a lacklaster solution now in case they do more than anticipated.

The budget is, lets say, in flux and can't really say. I have looked at the P4300s, and they inside my price range.

10 years seems a bit unrealistic.

I know, but our current servers are all 8+ years, and getting budget approval to upgrade them has been something I've tried for the past few years to no avail. I don't see that trend changing. It's just fiscal reality of my employment.

I tried using ReadyNAS once upon a time for Home directories. To say it couldn't keep up with user demand is an understatement.
posted by jmd82 at 1:44 PM on February 5, 2013


10 years is not unrealistic if you go big. I deal with clients with 15 year old Proliants that are still kicking along. The secret is that they aren't being asked to do much more than they were asked to do when installed.

I'm not really in the SAN end of things, but these are good recommendations for any IT purchase, especially if it needs to be highly available and last a long time.

1- Buy from a known, popular brand that sells a lot of stuff. You will have access to parts and expertise no matter who is running the shop 8 years from now. There is nothing worse than spending $8000 on a server only to have no parts or service available 3 years down the line. Spend the $15k on an HP or Dell. Get as little vendor lock-in as possible- buy equipment that you can get serviced through the manufacturer, or through third party servicers. (This is a huge cost sink in some purchases. Some vendors make it very difficult for third parties to work on their stuff, and are *really* expensive to have the manufacturer repair.)

2- Buy something modular. For the vsphere cluster, maybe a blade chassis that you can plug newer/better/more machines into as time goes on? Make sure your equipment has modular network adapters. Maybe you can only go with ethernet now, but in 5 years maybe you can move to fiber channel. (For example.)

3- Buy (or have the capability to upgrade) at least double what you need now. Never buy something like this maxed out, because you have no room to grow. It's way easier to ask for $1000 for some new processors or more memory than to say "hey, we need another $8 grand because we ran out of capacity."

4- Work with a reseller that will teach you what you need to know.
posted by gjc at 4:32 PM on February 5, 2013


I'd highly suggest tapping into the various EdTech mailing lists and communities out there and figuring out what other schools use, especially with Mac clients. There's a lot of voodoo around exactly what works (and what actually works), especially with OS X profile sharing. Some SAN solutions have absolutely pitiful Mac support. (You also realize you'll need at least one Apple machine to act as your host for OS X Server, even if you have virtual OS X Servers on top of that?)

A simpler NAS solution might fit the bill at much lower cost and complexity. It might also make sense to separate the home directory storage issue (i.e. get a bigger disk array or upgrade the disks in your existing array if possible) from the virtual machine disk hosting issue, especially if the virtualized servers don't have to care about the home directories. A lot of schools also don't even bother providing centrally shared home directory space for students (or anyone) on OS X; everyone can use Google Drive, flash drives, Dropbox, etc... for personal storage needs and just use shared storage for big projects and reimaging.

I'd agree that 10 years seems like an extremely long time for any solution. I understand that your budget isn't going to magically improve, so I feel like focusing on simpler solutions that are more inexpensive, maintainable, and replaceable after a reasonable lifespan. Avoiding licensing and support costs would be a plus too. Keep in mind that SATA drives first started shipping about 10 years ago, and nowadays many motherboards don't even have plain old ATA support. Not to mention the increase in disk capacities...

It doesn't sound like you're in a position to want, need, or possibly afford a grand solution that will magically address all your needs. You're worried about being hampered by a lackluster solution later, but I'd also be worried about being buried by an overcomplicated and overpriced solution now.
posted by zachlipton at 4:35 PM on February 5, 2013


Lastly, keep in mind that "fault tolerance" and "high-availability" have different meanings in this world than you might expect. Different vendors and products use the terms differently, of course, but there's a vast difference between needing a system where an administrator or automated monitoring process can slowly migrate a failed VM to another host and one where a 30-minute outage can cost a business millions. A certain level of fault tolerance would require multiple disk arrays, multiple controllers, multiple switches, multiple hosts, and multiple virtual machines on those hosts, along with a whole host of monitoring and control systems to detect failures and react accordingly. Even then, you have single points of failure around the power supply, physical environment, and of course that hidden dependency that wasn't as redundant as you thought.

You'll need to figure out what kind of reliability you truly need, based on your business cases, and what sorts of failures you can tolerate accepting.
posted by zachlipton at 5:09 PM on February 5, 2013


Worth looking into, some of the big players will take this on as a managed service for you. If you don't have the skills and knowledge in house (and don't want to bother with it), then it might be worth looking into. EMC (who own VMWare) for example offer this, as do all the large storage players.

That means they will handle migrating to the latest version, future-proofing your solution as time goes on (for the length of the contract).

This of course comes with the usual pros and cons of managed services.
posted by Admira at 8:06 PM on February 5, 2013


You need to be very very careful here. A lot of storage products don't actually work as advertised, or have enormous hidden costs. Ten servers and 500 users makes you a very small customer -- but don't expect any vendor to tell you that. Instead they'll give you a great deal on their most complicated, overengineered product which requires tons of bundled services and support. This is an easy way to lose hundreds of thousands of dollars of your employer's money.
posted by miyabo at 8:57 PM on February 5, 2013 [1 favorite]


Thanks for the responses, they've definitely given me some ideas to chew on.

Good point about fault tolerance. My fear is our storage goes down and the entire system goes down. Can we live without for a day if it means save tens of thousands of dollars? Most likely. Any more than a day or a few hours? I'd probably loose a liver in the process.
posted by jmd82 at 8:30 PM on February 6, 2013


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