Server Redundancy for a Small Business? 81
SadPenguin asks: "I am currently working for a small company of about 15 people each with one to two workstation/laptop machines a piece. We are looking for a new server solution, as our last one crashed, and lacking any server redundancy, we nearly lost all of our data since our last backup (it was only a few days, but an important few). What the kind of server (and redundancy) solution would be appropriate for a company of my size? Most advertisements are for large scale enterprise serving solutions, but these are costly and excessive for my situation. I'm sure that there is a simple Redundant Server technology out there that is a bit less costly, but won't result in any downtime in the event of a motherboard component failing (like we faced this time when our mysterious surface soldered VRM failed). So what do you use? What should I use?"
A few recommendations. (Score:5, Informative)
I actually run a computer consulting firm specializing in small businesses. I'll outline some of the more common recommendations - with what I think is the most important first.
From my experience, the best approach is to layer your defenses. I'd REALLY recommend a UPS (I generally assume this is purchased with a server, but it isn't always) at very least. Your local power company is only required to provide you with something CLOSE to 120v. They generally can't keep it consistent enough for power supplies (and electronic componentry in general). Protect your investment, UPSes are generally relatively cheap.
The fact that you've got a backup solution is good, but (as you've seen) not enough. Evaluate it, and see if it's consistent with best practices - i.e., is it a tape (or optical) backup system that is done in rotation and taken offsite by somebody in the company? If not, set that in motion first.
Next, some sort of drive redundancy is in order. At very least, mirror your drives. I generally recommend RAID5 (or one of its variants), but in very small companies RAID5 isn't either required or affordable or both. IMO, the jury's still out on the long-term viability of IDE RAID, but I think it looks promising.
Finally, redundant power supplies and NICs (for those of us that are REALLY paranoid ;) ). I've had a couple of servers' power supplies die on me, but the server kept right on ticking thanks to a redundant unit.
If it's affordable to your company, consider hot-swappable server components, as well. This significantly reduces downtime to your coworkers... and expense to your company.
Hope this helps. Good luck!
Oh yeah, FP ;)
Our backup system (Score:5, Informative)
If the main fileserver goes down I simply change the configuration to read/write and change filemaping on the users machine and they continue to work. The whole process will take about 10 minutes to reconfigure the server and a couple of minutes per user machine.
As a bonus I dont delete the intermediate versions of changes files as I update the server. Instead I compress them with a unique filenames. So I can recover a fairly complete history of any given file. I have yet to fill up the 80gb drive so I havent needed to delete any backups. When the backup drive is full I will start deleting some of the older version, I should have room for about 6 to 9 months of backups at 15 minute intervals.
Cheap Redundancy (Score:5, Informative)
* two identical servers, running linux (of course).
* heartbeat
* drbd
* two UPS
Notes, Ins, Outs and What Have You's
service redundancy
heartbeat is used to make 2 servers look as if they were one. if one of the servers dies, heartbeat makes sure the other assumes the ip address and has all the relevant services started.
data redundancy
drbd is a network block device. again, it looks like one device, but when data is written to it, its actually being written to 2 seperate locations. if one box goes down, heartbeat makes sure drbd makes the other box primary.
hardware
these two call for a dedicated network and serial connection. so 2 nics and a serial port per box.
definitely raid array of some sort.
see drbd.org for more details.
this is not a 100% proof setup, but its cheap and covers most of the bases.
of course, it requires a linux dude to get it all to work.
If you're using Linux (Score:4, Informative)
If you have appropriate hardware you might also appreciate Stonith [linux-ha.org], which provides forced-shutdown of a failed node (in the case that the failed node won't release the IP address, and hence you would otherwise have problems switching service).
If you're in the UK then give me a shout and I'll set it up for you (for a reasonable fee)! My contact details are available on my web site.
Re:A few recommendations. (Score:4, Informative)
The first red flag I saw was that although they had backups, they were three days old. If the data is worth saving, it's worth doing it right. Full backups on the weekends and incrementals nightly.
Ok, the redundant stuff... power supplies, hot swap drives, RAID5. You're approaching a $10k configuration. That, BTW, would have still gone down because they had a motherboard failure. And since they needed backups, their drives were corrupt, so the RAID probably would have been too.
Really though, this whole question is about designing their new server without any idea of the load required. Based on the info that is available, I think I would lean towards purchasing two servers. Make them a little smaller than what you would purchase if you only had one, and divide the load between them. If one fails, you can temporarily transfer to the remaining one until you can get it fixed. You could even go so far as to move drives and RAM temporarily if necessary. Just make sure the equipment is server rated. IE: my Dell 400sc Poweredge servers are rebadged desktop machines. My Compaq Proliant 800s are definately not. Even good equipment is getting pretty cheap if you have reasonable requirements.
Above that; daily backups. The UPS equipment like you suggested, just keep in mind that UPSs are consumables. And possibly IDE RAID-1. Drives are cheap and 15 users shouldn't need the performance of SCSI.
Rsync (Score:4, Informative)
I would suggest springing an extra $90 to get two extra gigabit ethernet cards and a crossover cable for a dedicated connection for rsync which doesn't compete with office traffic.
Using rsync as a basis, the solution could be made as low tech and simple or automated complex as you feel is needed.
-Pete
Do woodworking? 50 Router Bits [starvingmind.net]
A couple of solutions (Score:4, Informative)
If you are using Linux/UNIX/*BSD, you could use Rsync [samba.org]. There was a great article explaining Rsync usage in the June '04 print edition of SysAdmin [sysadminmag.com].
Re:If you dont see (Score:3, Informative)
* Small business owners are CHEAP. They don't want to spend a nickel on something that isn't an immediate problem.
* They don't see the value in disaster recovery until they experience the disaster.
* They are hard to sell and market to.
* They often use horrible niche-market server based solutions that are Windows only.
I spent a few weeks talking to various business owners about a solution that would offer the following:
* Redundancy, in many of the same ways discussed here,
* Security: firewall, antivirus, antispam
* Offsite backup and admin
* Four hour replacement
* Other stuff, potentially, like ad blocking, web whitelists/blacklists, fax server, email server, etc.
The price to do this for a small business would have to be at least $250/month. They won't spend it on something that they see as intangible. This is the reaction, even considering that at least $200 a month is spent by them in man-hours to have someone, often the owner, wrestling with the cheapo Windows server that they're using. Keep in mind that the $250 would include DSL connectivity AND the hardware for the box.
Jonathan