I am thinking of the best method for maximising uptime on a single server (running Win2K).

I have a choice between using RAID 1 SCSI or, having a twin disk with a periodic backup from one disk to another - something like ultrabac. I'm planning to avoid tape backups altogether and rely on disk based backups for speed and cost reasons.

I appreciate that RAID 1 has the benefit of hot standby should the harddrive fail. But, if somebody does some file damage to the main RAID disk, it gets copied onto the backup disk.

With the ultabac solution, there is more downtime should a failure occur with the possibility of lost data ?

Are these two statements correct ?

In either of these situations, should the server hardware itself fail, can I (in principle) rip the disk out of the server and pop it into another server with a few config changes e.g. a job that could be done within a few hours downtime?

Which would you do in my situation. We are talking about a valuable webserver with a SQL Server backend.


Please help !

Thanks

As far as I know, your statements are correct. That's why RAID is NOT a backup solution/replacement. You use RAID to avoid downtime in the case of a drive failure and backup to restore corrupted/lost data.

In theory you could remove the disk from one machine and run it in another but I'd advise you to have another machine with IDENTICAL hardware. And I mean really identical even down to the revision number on the various pieces.

What to do depends entirely on how valuable it is to be up all the time. If it's really valuable I'd setup a system with 2 independant machines each with their own system disk and either use dual ported raid or some sort of mirroring to keep the site data in sync across them.

Thanks for your reply jnestor.

Looks like I still need a tape backup.

What about the disk backup solution ? Any good or do people recommend tape backups ?

First of all, switch from Win2K to Linux and you will see a tremendous increase in uptime. ;)

More useful info:
We installed a database server for a client who requires good reliability. The server is used for medical information collected from patients during clinical trial visits. Since a variety of people access this information during the daytime, synchronizations and backups etc. are done at night. The server basically runs 24/7.

The clinic would be hosed if the server was to drop offline during the day. This happened three years ago and they had tremendous problems tyring to get patient data, etc., thus slowing down the study and pissing off a lot of people who showed up to the clinic but could not be helped.

Our Solution
To overcome this, we installed a custom built server: including:

Dual Power Supplies:
I do not think that this was really necessary, but we had a server case that had dual powersupplies donated.

RAID 1
We also installed a RAID 1 system using an Adaptec Controller. We used an ATA card instead of SCSI, but the perfomance was good. We installed a bootable RAID 1 ATA 66 drive cluster with the sytem and applications. The second drive cluster stored the database files.

Tecmar NS 20 Tape Drive
We used tecmar NS20 tape drive (20GB) that gets manually rotated on a weekly basis. We use four different tapes.

DVD-RAM
On a monthly basis, the database (~3GB) is burned to DVD. This is mainly for security and long term record keeping purposes. The DVDs are shipped off-site.

UPS
APC Smart-UPS 1400 with management software.

Spare Machine ....(PII Dell Server)
On a weekly basis, the database application and files get copied to a spare machine. This machine does not offer RAID or any backup but is used as a hot standby. We have the machines hooked up on a 100MB network and schedule the data transfers at nights. This works well. Also, the database app has a script to verify that not data was corrupted during transfer.



Costs
Getting high reliability comes at a price. The UPS alone was around $600, another $600 for drives, $450 for the Tape Drive, $350 for the DVD-RAM, $350 for the RAID controller -- plus motherboard, proccessors and RAM.
I belive the entire system came to about $4500 -- and we had the $450 case donated.

Thanks huck for the little success story.

However, I do not have a choice and have to use a Win2K server. Given a choice, I would move many more services to a Unix based system but my hands are tied :angry:

Seems that the best solution for a high-uptime single server is: SCSI drives, RAID 1, tape backup

Interesting idea that a DVD is burned one a month, I might try that to provide long term backup and some historical stuff.

Otherwise, I'm planning to run a large SQL Server based website and large MySQL based application all on one large dual 1.2 G CPU server with the above attachments - its the only package I can afford at the moment. My question is:

How Stupid is this ?????

and

Will I regret this later

When you say large database and dynamically driven web site? How large do you mean? Also, what about security? What would happen if someone hacked into your database via the web server?

For mission critical systems or sensistive data, I tend to put the database and the web server on two different machines. The main reason is security although internal access to the database may also be required.

By using two machines, you do two things:
1.) Load balancing -- you can optimize one machine for web serving and the other for database work.
2.) Security -- typically we install our databases on a dedicated machine and use firewalls to control access.

Okay, that probably was not much help because you only have one machine.....


Why use SCSI disk?
SCSI is nice and has great performance, but do you really need that performance. You can get ATA100 RAID systems, which pump out data pretty quickly. You could probably afford to buy 4 ATA/IDE disk for the price of 2 SCSI disk. This way you could put the system on one set and the database on the other. By splitting this up, you would probably see a greater performance boost than using SCSI. However, you know your needs -- so if you need that high disk throughput, SCSI is definitely the way to go.

RAM, RAM, and more RAM.
Be sure to pack the box with RAM. If you are planning on running a database backed web site using ASP, JSP, or something similar, you will need a lot of RAM. Basically, almost any Win2K server needs at least 256MB of RAM just to get good results with email, ftp, and http. Add onto that database work and you will need more RAM. I would suggest installing at least 512MB. Hopefully, your motherboard uses inexpensive RAM. After setup, monitor your RAM usage at peak times and make sure you do not have to use virtual memory -- if you do, your servers performance will take a huge hit.

Tape Drive
How much data do you have to back up and how often?
Can you manually rotate the tapes every so many days?
We used the Tecmar NS 20, which suited our needs. There are higher compacity tapes out there -- you may want to check one of those. Also, if you are backing up a live web site, consider the impact of the backup process on web site access times and server resources.


You really can't use Linux -- MySQL performs much better on linux than on NT ( at least that is what I've heard). I face a similar situation once -- I won be telling the client that they would save the licensing fees for both the SQL Server and Win2k. Most of the time, I loose the linux argument though...