On Fri, Nov 30, 2012 at 4:40 PM, Sebastian Riemer <sebastian.riemer@xxxxxxxxxxxxxxxx> wrote: > On 30.11.2012 15:27, Sebastian Riemer wrote: >> On 30.11.2012 14:25, Oguz Yilmaz wrote: >>> What is the suggested way for making Raid 0+1 (not 1+0)? >>> Is it possible to make it without LVM? >> >> Yes, it is possible but it only makes sense if you want to mirror to >> another server as most people know that the alternative DRBD is too slow >> for serious storage requirements. >> >> Create the RAID-0 first, then take your RAID-0 device and e.g. an iSCSI >> device from another storage server with the same setup and create a >> RAID-1 over them. Then, you've got your stacked MD layers. >> Why do we need another storage server. IF I create md0 Raid0 (sda1 + sda2) md1 Raid0 (sdc1 + sdc2) then is it possible to create md2 Raid1 (md0 + md1) like md? Regards, >> With the flag write-mostly you can even tell the read balancing that the >> remote device is slower than the local one. >> > > I've forgotten to mention: You need a kernel >= 3.4.2 for this. > > Earlier kernels don't support bvec merging and therefore every IO is a > slow 4 KiB IO in that RAID 0+1 setup. > > Btw.: LVM also supports striping but letting LVM do striping is only > useful if you want to build RAID 1+0. The speed is the same as "RAID 1+0 > + LVM". Only that raid10 driver doesn't scale good for >= 24 HDDs. -- 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
