I realise that what I am attempting is not very standard in terms of raid, however this is my logic and reasoning... I am setting up a home server that while on 24/7 will only be in use when either myself (linux) or my son (windows) are using it, so usage will vary and power concerns (Electricity in the UK is extortionately priced!) and longevity are important. My set up in theory is the following using GPT partitioning. >sda 6 partitions >>free space 1MiB >>sda1 bios_boot 1MiB >>sda2 /boot 200MiB raid1 md2 >>sda3 / 8GiB raid1 md3 >>sda4 *swap 9GiB (will be "raided" using pri=1) >>sda5 /download 40GiB raid10 md4 >>sda6 /thecube ~950Gib raid6 md5 >>free space ~20MiB > >sdb same as sda > >sdc 1 partition >>free space enough space to place sdc6 the same start as sda6 >>sdc6 /thecube same as sda6 >>free space > >sd[df] same as sdc The reason for partitioning this way is that all w.i.p. or downloads, torrents, etc. will first go into /download and once complete will be moved into /thecube for long term read only storage As /thecube is going to be used less often than sd[ab] it would be advantages to have sd[df] power down and when the system is not in use at all have sd[ab] also power down. This should increase the lifespan of the drives... and yes I do know that drives are more likely to fail when powering up, but I also have real life evidence when I used to work on AS/400s that they fail on power up if they have hardly ever been turned off more often than if they have regular power off/on cycles :-) I may even look at suspend to ram and magic packets if the system is not accessed in say 1 hour, although this is less likely to be implemented! Ok so that’s the reasoning behind the question. I do have a couple of related questions... I have already done some testing by setting up sd[ab] for md[2-4] but with no file systems on top, and then pulling sdb and then putting it back in. q1, why does -add throw up the message : not performing --add, re-add failed, zero superblock... q2, I setup md4 as a raid10 far 2, and I may not be understanding raid10 here; when I zero the superblock to add it as I did with the other raids which worked ok, for some reason it causes sda4 to drop out and kills the whole md4 raid. q3, Is it preferable to have a write intent bitmap, and if so should I put it in the meta-data as opposed to a file. Thanks in advance. Jon. -- 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
