> From: linux-lvm-admin@sistina.com [mailto:linux-lvm-admin@sistina.com]On > > striping or concatination? > > striping means yes same size spaces, but you can just concatinate which > simply means adding together. So 12+5+4= 21, you could then mirror against > the 20 gig in software and only loose 1 gig. Whether the controller is > bright enough to tell the difference is another matter. Oh yes I see what you mean now, I meant striping, it was implied. Could I concatenate the 12+5+4 into one volume and then stripe that with the 20? Or would that just be suicidal? oooh or the 5+4 striped, then stripe that with the 12 then the result with the 20? Resulting in... mental arithmetic... 36G in total. :) Its not a production machine by the way. Mostly its my TV. > > Thing > > -----Original Message----- > From: Steve Wray [mailto:steve.wray@paradise.net.nz] > Sent: Wednesday, 20 February 2002 3:54 > To: linux-lvm@sistina.com > Subject: [linux-lvm] lvm and 'poor mans raid' on heterogenous hard > drives! > > > Hmmmm, > Ok so I have 4 hard drives of very varying capacity > (20G,12G,5G,4G) > I have an off-board IDE controller (Promise 66) > > I think 'maybe I can take advantage of the IDE > system and put a drive on each master and stripe them.' > A hardware RAID card would be suboptimal because > (as I understand it) the striped volume could > only be as big as the smallest drive. > > So, I set up the drives as; > hda = 20G > hda1 = 64M and is /boot > hda2 = 1G > hdc = 12G > hdc1 = 1G > hde = 5G > hde1 = 1G > hdg = 4G > hdg1 = 1G > > The other partitions are set up for various other volume > groups and non LVM system partitions. > > hda2, hdc1, hde1, hdg1 are added to a VG 'fast' > > The other LVM partitions on hdc-g are in a volume group that > doesn't see much traffic, just storage. > > I make logical volumes on fast striped across 4 drives. > So thats 4 partitions at the beginning of the drives, > with volumes striped across them. > > I expected some performance improvements. > > So I get the iozone benchmark and start running it on the system. > I compare performance of striped volumes with performance of a volume > purely on hda. > > Interestingly, the performance improvement is not dramatic, > I expected better. The main improvement seems to be that the > striped volumes do better with larger file sizes and as file size > increases the striped volume keeps its performance up better. > > I'm a newbie at this benchmarking lark, so if anyone wants > the excel spreadsheets generated from iozone just ask, > I'd like a second opinion! There are some strange things, > like when file size gets above 16M performance drops dramatically > regardless of striped or linear volumes... Maybe its something > to do with extents? > > > > > > > _______________________________________________ > linux-lvm mailing list > linux-lvm@sistina.com > http://lists.sistina.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html > > _______________________________________________ > linux-lvm mailing list > linux-lvm@sistina.com > http://lists.sistina.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html > _______________________________________________ linux-lvm mailing list linux-lvm@sistina.com http://lists.sistina.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html
