Re: High-availability question

Pavel Machek (pavel@bug.ucw.cz)
Mon, 1 Jan 1990 07:11:45 +0100


Hi!

> Hope this is not too much off-topic. I have a client who wants to setup a
> high-availability linux server network. It's an ISP, so we're talking
> mail/web/ftp/dns/etc. I would like to have 2 identical boxes, with
> identical harddisks partitioned the same way, and to have the main box
> constantly synchronize it's filesystem with the standby box, so that when
> it fails, the standby just does an IP takeover, and has all the recent data
> in place. I would really like to do this on the lowest possible level,
> something like 'write this block to head x, cylinder y', instead of doing
> cp over nfs every 5 minutes or so. Is there anything available that would
> do something like that? If not, how easy would adding this to the kernel
> be? Can it be done it all? My idea was to have the standby box run a
> custom init binary, that would just sync the disks and wait for the other
> box to die. When it dies, it runs the real init, everything comes up, and
> the box takes over.

raid1 over localdisk and nbd-mounted disk from other host is the
answer.

Pavel
PS: Of course, you'll need fsck before mounting read-write.

-- 
I'm really pavel@ucw.cz. Look at http://195.113.31.123/~pavel.  Pavel
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