On Thu, 15 Apr 2004 robin-lists@robinbowes.com wrote: > Does this look feasible? Can you see any major gotchas? Any better > suggestions? Personally I'd keep life simple at the expense of a little disk space - my layouts are also based on wanting to split partitions to, so I'd never put /, /usr and /var on the same partition - historical reasons, including fsck time and maybe a distrust of very old PDP11 Unix systems... (Yes, I'm a boring old fart) Anyway what I do with my own machines (and those I build for others) is as follows: Partition each disk identically. That way, if you need to swap out a drive, you already have a copy of what it's partition table ought to look like by simply looking at the other drives - sort of self documenting if you like. So for a single disk system it might look like: sda1 256MB / sda2 1GB swap sda3 2GB /usr sda4 Rest of disk /var Actually, /usr might be less and swap would be double memory, but you get the jist - use the 4 primary partitions and usually no more. In olden days consideration would be made to where the disk head spends most of its time - here, oscillating between the /usr (programs) and /var (data) might be optimal, but I don't think anyone cares about this these days. (historically, /usr was where users home directories lived too, then the head would be between /usr and swap and /bin with special programs having the 'sticky bit' set to make them reside in memory or swap to make them quicker to load) Partition the drives similar to this in a RAID system too. Then combine them as follows: sda1 and sdc1: RAID 1 / sda2,b2,c2,d2: RAID 5 swap sda3,b3,c3,d3: RAID 5 /usr sda4,b4,c4,d4: RAID 5 /var You "lose" 2 partitions: sdb1 and sdd1. You can combine these in another RAID1 if you like, but it's not much use for anything. Putting swap on RAID5 probably isn't optimal, but if your machine is swapping heavily, buy more memory. If you are really tight on disk space and know you have plenty of RAM no swap is probably better than too little swap. You might need to adjust the sizes of the swap and /usr partitions - I usually aim for 2GB under /usr (that would be 4 x 768MB partitions under RAID5) - I've found that to be enough for Debian and X and space for other stuff, but YMMV. Remember with a 4-disk RAID 5 system you get 3 times the capacity. Debian also puts /home under /, so I always remove it before creating any users and create a /var/home and symlink /home to /var/home. If it's just a home server and you don't anticipate the log files growing, you may want to consider not having a separate /var partition and mounting that as /home instead... You need to make sure you can actually boot off sdc1 should you ever lose sda. This is vitally important! Most SCSI controllers allow you to change the boot drive, so it shouldn't be a problem, but it might mean manual intervention should you need to reboot it in a degraded mode. I've not used a /boot partition for about 8 years now. As far as I'm aware it was just a "hack" when BIOSes couldn't boot from cylinders > 1024, and putting / on the very first partition sorts this anyway. /boot on my servers is just a directory under / on all my machines. Knowing that you are only using 4.3GB drives, I might be tempted to merge the /usr and /var partitions. Enjoy, Gordon - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
