Some good suggestions here, thanks guys. Do I >DID< imagine some built in support for making use of this space? As a side note. when i do a repair or check on my array.. does it check the WHOLE DRIVE.. or just the part that is being used? I.e. in my case.. I have a 1TB drive but only an array multiple of 500GB.. i'd like to think it is checking the whole whack as it may have to take over some day... ----------------------- N: Jon Hardcastle E: Jon@xxxxxxxxxxxxxxx 'Do not worry about tomorrow, for tomorrow will bring worries of its own.' ----------------------- --- On Tue, 22/9/09, Majed B. <majedb@xxxxxxxxx> wrote: > From: Majed B. <majedb@xxxxxxxxx> > Subject: Re: Full use of varying drive sizes? > To: "Linux RAID" <linux-raid@xxxxxxxxxxxxxxx> > Date: Tuesday, 22 September, 2009, 2:07 PM > When I first put up a storage box, it > was built out of 4x 500GB disks, > later on, I expanded to 1TB disks. > > What I did was partition the 1TB disks into 2x 500GB > partitions, then > create 2 RAID arrays: Each array out of partitions: > md0: sda1, sdb1, sdc1, ...etc. > md1: sda2, sdb2, sdc2, ...etc. > > All of those below LVM. > > This worked for a while, but when more 1TB disks started > making way > into the array, performance dropped because the disk had to > read from > 2 partitions on the same disk, and even worse: When a disk > fail, both > arrays were affected, and things only got nastier and worse > with time. > > I would not recommend that you create arrays of partitions > that rely > on each other. > > I do find the JBOD -> Mirror approach suggested earlier > to be convenient though. > > On Tue, Sep 22, 2009 at 3:58 PM, John Robinson > <john.robinson@xxxxxxxxxxxxxxxx> > wrote: > > On 22/09/2009 12:52, Kristleifur Dađason wrote: > >> > >> On Tue, Sep 22, 2009 at 11:24 AM, Jon Hardcastle > >> <jd_hardcastle@xxxxxxxxx> > wrote: > >>> > >>> Hey guys, > >>> > >>> I have an array made of many drive sizes > ranging from 500GB to 1TB and I > >>> appreciate that the array can only be a > multiple of the smallest - I use the > >>> differing sizes as i just buy the best value > drive at the time and hope that > >>> as i phase out the old drives I can '--grow' > the array. That is all fine and > >>> dandy. > >>> > >>> But could someone tell me, did I dream that > there might one day be > >>> support to allow you to actually use that > unused space in the array? Because > >>> that would be awesome! (if a little hairy re: > spare drives - have to be the > >>> size of the largest drive in the array > atleast..?) I have 3x500GB 2x750GB > >>> 1x1TB so I have 1TB of completely unused > space! > >> > >> Here's a thought: > >> Imaginary case: Say you have a 500, a 1000 and a > 1500 GB drive. You > >> could JBOD the 500 and the 1000 together and > mirror that against the > >> 1500GB. > >> > >> Disclaimer: > >> I don't know if it makes any sense to do this. I > haven't seen this > >> method mentioned before, IIRC. It may be too > esoteric to get any > >> press, or it may be simply stupid. > > > > Sure you can do that. In Jon's case, a RAID-5 across > all 6 discs using the > > first 500GB, leaving 2 x 250GB and 1x 500GB free. The > 2 x 250GB could be > > JBOD'ed together and mirrored against the 500GB, > giving another 500GB of > > usable storage. The two md arrays can in turn be > JBOD'ed or perhaps better > > LVM'ed together. > > > > Another approach would be to have another RAID-5 > across the 3 larger drives, > > again providing an additional 500GB of usable storage, > this time leaving 1 x > > 250GB wasted, but available if another 1TB drive was > added. I think this may > > be the approach Netgear's X-RAID 2 takes to using > mixed-size discs: > > http://www.readynas.com/?p=656 > > > > Cheers, > > > > John. > > -- > > 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 > > > > > > -- > Majed B. > -- > 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
