Freddie, Thanks! I have to say that this is the most cogent explanation on how to prepare ZFS drives that anyone has ever given me.
Thanks again! Joe Joe McGuckin ViaNet Communications j...@via.net 650-207-0372 cell 650-213-1302 office 650-969-2124 fax > On Jan 12, 2021, at 10:32 AM, Freddie Cash <fjwc...@gmail.com> wrote: > > On Tue, Jan 12, 2021 at 10:10 AM joe mcguckin <j...@via.net > <mailto:j...@via.net>> wrote: > Folks, > > I want to buy some 16TB drives and raid them up > > How should I label and prepare the drives for ZFS? Someone ought to write a > ‘cookbook’ on that! > > If these drives will be strictly data drives (not booting from them), > partitioning them is fairly easy. You will want to determine a labelling > system for them. Personally, I like to label the drives using a grid system > (columns are letters, rows are numbers). For systems with multiple JBODs > attached, I include which JBOD chassis their in as well. For example, a > 24-bay chassis would use disk-a1, disk-a2, disk-a3 ... disk-d4, disk-d5, > disk-d6. A system with 2 24-bay JBODs would use jbod1-a1, jbod1-a2, jbod1-a3 > ... jbod2-d4, jbod2-d5, jbod2-d6. So you label the GPT partition on each > disk, and build the pool using the GPT partition labels. > > gpart create -s gpt da0 > gpart add -t freebsd-zfs -a 1M -l disk-a1 da0 > > gpart create -s gpt da1 > gpart add -t freebsd-zfs -a 1M -l disk-a2 da1 > > And so on. Add 1 disk, partition/label it based on its location. Then add > the next disk. And so on. > > Then use the GPT labels to create the pool (they show up as devices under the > /dev/gpt/ directory): > > zpool create mypool mirror gpt/disk-a1 gpt/disk-a2 mirror gpt/disk-a3 > gpt/disk-a4 mirror gpt/disk-a5 gpt/disk-a6 > > > If you need to boot from these drives (make a root pool), then things get > more complicated. Personally, I'd recommend using the 16 TB drives strictly > for a data pool, and then use some smaller SSDs for a root pool, in a simple > mirror vdev setup. Separate the OS from the data. :) > > Do I need to start the volume on a particular sector boundary? > > The "-a 1M" argument for gpart does it for you. It aligns the partition at > the 1 MB boundary, and figures out which sector of the disk that corresponds > to based on the sector size of the disk (512B or 4K). > > Are the 4096 byte sector drives usable? > > Yeah, they work without issues. Try not to mix 512B and 4K drives within a > single vdev (it'll work, but may cause performance issues). Mixing them in a > pool (a vdev using 512B drives, another vdev using 4K drives) is okay, so > long as you set the vfs.zfs.min_auto_ashift sysctl to 12 (force the minimum > block size used by ZFS to be 4K). That way, in the future, you can replace > the 512B drives with 4K drives without any performance issues. > > You can check what the ashift value is for each of the vdevs using: zdb | > grep -B5 ashift > > If it shows ashift=9 anywhere, then destroy the pool, change the sysctl > value, and recreate the pool. Check to make sure it shows ashift=12 in zdb > output. > > -- > Freddie Cash > fjwc...@gmail.com <mailto:fjwc...@gmail.com> _______________________________________________ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
