RAID 5 QuickMirror

[benace]

Hey All-

I have a Compaq ML530 with (3) 36.4gb hard drives in a 6-drive bay. They are setup in a RAID-V array, such that all drives are combined into one physical drive.

Now, this is one of my mission critical servers - IE it can _not_ go down for more than an hour or so. I have a set of 3 identical drives. I want to make an image copy of the three active drives, onto my 3 spares. I will then store the spares in a locked cabinet, in the event of (God forbid) my server catches on fire or whatnot. That way, I can pop the inactive drives into another identical server, restore the latest backup data from tape, and be off and running in no time.

Questions is - what is the best way to get a mirror image of the active drives onto my backups w/o taking the server down? We do have the tape backup copy that runs every night, but having to re-install the OS, configure the server, and then restore from the backup would cause too much down time. Any help much appreciated. Thanks!

-ben

Ben McMahon
Information Technology
ben.mcmahon@perrysicecream.com
Perry's Ice Cream

 

[meireles]

Hi,

Your idea is ingenious, but is maybe not the best way to go. Of course, there are speciality high availability solutions (clustering, online backups, off-site real-time replication, etc.) but I suppose you're instead looking for a cheap, not too complicated, quick-and-dirty solution. I have some suggestions for you:

1 - Use Symantec Ghost. You can take your machine offline, boot from a network-ready DOS floppy, create an image of your disk to a network drive an burn it to a CD or DVD. If you ever need to restore the disk, boot from a DOS floppy with Ghost and restore from the image on the CD/DVD. This is the easier approach.

2 - Use VMware GSX. Use your current machine as a VMware GSX host, and create a virtual machine to do whatever tasks your server is currently performing. A VMware virtual machine is just a bunch of files on a disk, so suspending the machine for a couple of minutes and copying those files to elsewhere is all it takes to perform a full backup. You can even use this as your daily backup solution. I manage 6 VMware GSX Servers that are running more than 40 virtual machines, and that's the way I back them all up.

3 - Use a backup solution that supports OBDR. OBDR means "One Button Disaster Recovery", and it's a software/hardware solution; both the backup software and the backup device (ie, the tape) must support OBDR. Of course, this may involve aditional investment if your current backup solution doesn't already support OBDR. It works more or less like this: let's suppose your machine crashed; you power up the server with last full backup on the tape drive, while pressing a button on the tape drive; now, the tape drive will be recognized as a bootable CDROM, and the server will boot from it; there, you have a console that will allow you to restore the whole machine from tape. This rough description greatly depends on the software/hardware you're using. However, one thing is for sure: no need to install the OS first, and then restore from there - just restore it all directly from tape.

I hope this helps you make an informed choice. Personally, I'd go for Ghost on your particular case.

Regards,

Paulo Meireles

 

[technome]

Have you looked into server replication ? Have Double-Take fron NSI software and it works great. You could have automatic failover which would switch to a secondary server in moments. Another option ,which I use is a manual failover which can get the secondary server running as a replacement for the primary server within minutes. Double-Take replicates at the byte level, in real time. Sunbelt Software sell this at a discount ( not cheap). Doubletake can be demoed ( full version) for 30 days). The servers do not need to be hardware exact, but preferable. Overhead while running is minimal