As far as I know, you can only boot from RAID1. Guy -----Original Message----- From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid-owner@xxxxxxxxxxxxxxx] On Behalf Of Derek Piper Sent: Tuesday, January 11, 2005 2:14 PM To: linux-raid@xxxxxxxxxxxxxxx Subject: Re: RAID5 on different sized disks on low-end machine Hi, I revised my idea and thought about RAID 1+0 for some partitions, since there are 4 drives. This outline below might clarify what I was trying to mention earlier. Is this a feasible set-up that would be bootable (kernel compiled-in md, I'm no stranger to compiling kernels)? I'm interested to hear comments/opinions since I've never done this before. Like I said, it'll be running on a Dual-pentium pro 200 (W6-LI) machine, I have no idea if machines of that vintage have the 'cojones' for software raid or not. My ideas of RAID1+0 / RAID5 disk system partitions MB /dev/hde 60GB 57241 (from controller) /dev/hdf 60GB 57241 (from controller) /dev/hdg 60GB 57241 (from controller) /dev/hdh 80GB 78125 (unconfirmed) /dev/hd* = applies to all drives considered here Device MB Type GB Mountpoint MD device RAIDed size (MB) GB /dev/hd*1 20 RAID1 + 0 0.02 /boot /dev/md1 40 0.04 /dev/hd*2 192 RAID1 + 0 0.19 Swap /dev/md2 384 0.38 /dev/hd*5 2048 RAID1 + 0 2 / /dev/md5 4096 4 /dev/hd*6 2048 RAID5 2 /home /dev/md6 6144 6 /dev/hd*7 52933 RAID5 51.69 /data /dev/md7 158799 155.08 Does swap being raided make sense? I hear that sometimes it's a good idea since a disk failure won't make you crash and then I heard elsewhere that it doesn't matter and the kernel automatically raids swap partitions anyway. I prepared the above in a spreadsheet btw so I could work out partition sizes. Thanks in advance again for any comments. Derek On Tue, 11 Jan 2005 13:47:20 -0500, Derek Piper <derek.piper@xxxxxxxxx> wrote: > Hi, > > I am new to RAID / md devices, although I've used Linux for a number > of years. I decided it was high-time I had a RAID at home for > important things (email, web-sites, son's baby pics, mp3s etc.). I > happen to have a 3 Seagate 60GB hds and 1 80GB Seagate hd that I am > considering using for a RAID. > > My question is this, is it possible (and even a good idea) to use all > 4 hard drives as members of a 4 x 60GB RAID5 array by leaving 20GB of > the 80GB drive as a non-raided partition? I'll be using a Promise > Ultra TX2/100 controller. > > i.e. > > hde -> 60 > hdf -> 60 > hdg -> 60 > hdh -> 60/20 > > I heard about RAID6 too, though I'm assuming that will use up another > disk's worth of disk space too. > > i.e. RAID5 = 180GB usable size,wherease RAID6 = 120GB .. am I correct > in my thinking? > > I know many of you use far larger hard drives, I'm just trying to use > the components I already had spare from a number of machines and > reorganize to a RAID-backed fileserver. > > The machine is a dual pentium-pro 200 (320MB RAM) .. would that be a > dumb idea to use RAID5 on it because of the parity calculations > needed? > > Further to that, would it be a smarter idea to use RAID1 on all 4 of > some small partition(s) at the start of the disks to house > boot/root/usr partitions, and only RAID5 on a larger 'data' area of > the drive that is more likely to be read than written to? > > Comments are appreciated. > > Thanks, > > Derek > -- Derek Piper - derek.piper@xxxxxxxxx http://doofer.org/ - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
