I want to set up a multiple "mode" computer with four separate Centos installations on it. The objective here is to have a "spare computer" that I can boot up into any of four "modes" depending on what I'm swapping it in for a the moment. For example, I want to be able to boot it up as a webserver, or as a fileserver, or as a LTSP-enabled application server. And so on. I have a computer here with two 300GB hard drives in it, which I plan to split into four 150GB partitions, one for each of my "modes". And I want to install Centos separately and independently into each partition, so I can just tell Grub to boot up using whatever partition I choose. What is the best way to accomplish this? I have a bad feeling that the drive partitioning tool is going to complain about having multiple / partitions unless I take steps to avoid that. -- MELVILLE THEATRE ~ Melville Sask ~ http://www.melvilletheatre.com
----- Original Message ----- From: "Frank Cox" <theatre at sasktel.net> To: centos at centos.org Sent: Tuesday, December 18, 2007 1:20:01 PM (GMT+1000) Australia/Brisbane Subject: [CentOS] "multi-boot" drive partitioning I want to set up a multiple "mode" computer with four separate Centos installations on it. The objective here is to have a "spare computer" that I can boot up into any of four "modes" depending on what I'm swapping it in for a the moment. For example, I want to be able to boot it up as a webserver, or as a fileserver, or as a LTSP-enabled application server. And so on. I have a computer here with two 300GB hard drives in it, which I plan to split into four 150GB partitions, one for each of my "modes". And I want to install Centos separately and independently into each partition, so I can just tell Grub to boot up using whatever partition I choose. What is the best way to accomplish this? I have a bad feeling that the drive partitioning tool is going to complain about having multiple / partitions unless I take steps to avoid that. -- MELVILLE THEATRE ~ Melville Sask ~ http://www.melvilletheatre.com _______________________________________________ CentOS mailing list CentOS at centos.org http://lists.centos.org/mailman/listinfo/centos -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. Have you thought about virtualization ? What hardware are you planning on running this on ? -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.centos.org/pipermail/centos/attachments/20071218/d621c1d7/attachment-0002.html>
On Tue, 18 Dec 2007 13:44:38 +1000 (EST) "redhat at mckerrs.net" <redhat at mckerrs.net> wrote:> Have you thought about virtualization ? What hardware are you planning on running this on ?It's a new Intel Pentium Core 2 machine. I don't want to complicate this thing any more than I have to. I want to be able to put this machine in the corner and tell the guy who owns the place that if his webserver quits, he can put the spare online and hit "1", if the application server quits, put it online and hit "2" and so on. And 4 independent and separate Centos installations sounds like the easiest way to accomplish that, if I knew how to partition the disk. -- MELVILLE THEATRE ~ Melville Sask ~ http://www.melvilletheatre.com
On Mon, 2007-12-17 at 21:20 -0600, Frank Cox wrote:> I want to set up a multiple "mode" computer with four separate Centos > installations on it. The objective here is to have a "spare computer" that I > can boot up into any of four "modes" depending on what I'm swapping it in for a > the moment. For example, I want to be able to boot it up as a webserver, or as > a fileserver, or as a LTSP-enabled application server. And so on. > > I have a computer here with two 300GB hard drives in it, which I plan to split > into four 150GB partitions, one for each of my "modes". And I want to install > Centos separately and independently into each partition, so I can just tell > Grub to boot up using whatever partition I choose. > > What is the best way to accomplish this? I have a bad feeling that the drive > partitioning tool is going to complain about having multiple / partitions > unless I take steps to avoid that. >Fajar's post provides a simple way and seems to be what you're looking for. The key is that one boot image can have different root file systems specified using the same kernel. So, configurations can be "pre-loaded" in each FS to look like the failed node. BTW, adding one more configuration that has the sole purpose of acquiring and applying changes to the other local images would be a good idea. It's only natural that over time some configuration changes will occur and one will forget or make an error when trying to replicate those changes to the spare. However, as mentioned by another poster, letting it set may lead to it being non-operational when needed. Cmos batteries expire, things age, dust collects, power surges get past various protections, etc. I did something similar to this back in 199(twoish?) with a network involved on a real UNIX 5.X system, that had NFS/RFS available, to protect my client in case of HD failure (the most likely scenario then IMO). All nodes ran continuously and user databases were distributed. Each node was sized to be able to hold both the OS and a copy of the largest 2 live data bases on any node (hoping that only one node would fail at once, but allowing for two). A cron entry did cross-copy of any changed components (excluding node-specific ones) during the wee hours of the morning and a small report was generated that let us be sure the "backups" had completed successfully. A tape backup of all that on the least loaded node was then done in background at low priority. It was not intended for the end-user to be able to automatically bring the "spare" into the mix as a replacement for a failed unit, but it was intended that I could quickly adjust it to do so. This would require only changing shared stuff (using RFS at the time) on the replacement and activating those shares. I think I also changed the node reference on the "clients", IIRC. Anyway, with RFS, that was quick and easy. I liked RFS a lot and was sorry to see it eventually go away. Sure enough, a drive failed eventually and I came away looking like a hero. With todays equipment, you should be able to have the spare "sleep", awaken, receive any changes you like, and go back to sleep. A small report before re-sleeping will allow you to be sure that all is well with it. -- Bill