On 01/01/2015 04:24 PM, Kevin O'Gorman wrote:
On Thu, Jan 1, 2015 at 12:51 PM, David Christensen < dpchrist@holgerdanske.com> wrote:On 12/31/2014 01:57 PM, Kevin O'Gorman wrote:I've just gotten 4 4TB drives to replace my 4 2TB drives. I'm wanting to have one normal 4TB drive and one logical 12TB drive, so I will make three physical drives into one group, one logical volume and one partition support the big partition. My system actually resides on a fifth: an SSD drive. I am not interested in RAID, and I'm not sure striping would even help. I just have gigantic files I need to create and process once in a while, so it's really temporary space.mdadm RAID 0 should be the simplest approach for the 12 TB. Thanks for this advice. I'm looking into it. My first impression isthat it's not so simple. - I installed mdadm, but I'm a bit puzzled that it dragged in postfix with it. I set that up as local only, because I don't do mail on this system. - The first document I looked at, https://raid.wiki.kernel.org/index.php/RAID_setup talked about probems putting a RAID in /etc/fstab, and while it mentioned that persistent superblocks solved this problem, it did not say much about how to set it up such as what the fstab entry would look like My mobo has 5 SATA 3 interfaces. They become /dev/sda ... /dev/sde more or less at random, perhaps depending on how quickly the drives spin up. I had to put GRUB on all drives. I really need stability in whatever I set up. Any thoughts?
Please "reply to list".One of my complaints about Debian's installer is that it installs recommended packages, recursively, by default. When I wanted to build a kernel with realtime patches, this meant ~700 MB of stuff I didn't want. I now use 'apt-get' with the '--no-install-recommends' option to avoid this problem.
Understand that with FOSS there are learning curves no matter which approach you pick. That's part of the price you pay for "free". I've never used mdadm. I learned enough LVM a few years ago to set up swap and root on encrypted partitions and to set up JBOD data drives. Administration of LVM file systems is basically the same as ext file systems. But, the extra layer between the file system and the hardware becomes a hassle when I want to boot the installer media into rescue mode and mess with raw file systems on system drives (for backup and restore). More recently, I learned enough zfs-fuse for single and mirrored data drives. I later migrated to ZOL for performance. Administration of ZFS file systems requires a lot more knowledge and planning. And since ZOL is not integrated into Debian, I had to invent scripts to get things mounted at boot and cleanly unmounted at shutdown.
Perhaps someone with mdadm experience can offer some pointers for learning enough mdadm to set up RAID 0.
As for the problem of which device is which /dev/* entry, the work-around is to identify them by UUID or some other means. Take a look at 'blkid' and the /dev/disk/by-* directories.
David