> From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- > boun...@opensolaris.org] On Behalf Of Matt Keenan > > Just wondering whether mirroring a USB drive with main laptop disk for > backup purposes is recommended or not. > > Plan would be to connect the USB drive, once or twice a week, let it > resilver, and then disconnect again. Connecting USB drive 24/7 would > AFAIK have performance issues for the Laptop.
MMmmm... If it works, sounds good. But I don't think it'll work as expected, for a number of reasons, outlined below. The suggestion I would have instead, would be to make the external drive its own separate zpool, and then you can incrementally "zfs send | zfs receive" onto the external. Here are the obstacles I think you'll have with your proposed solution: #1 I think all the entire used portion of the filesystem needs to resilver every time. I don't think there's any such thing as an incremental resilver. #2 How would you plan to disconnect the drive? If you zpool detach it, I think it's no longer a mirror, and not mountable. If you simply yank out the plug ... although that might work, it would certainly be nonideal. If you power off, disconnect, and power on ... Again, it should probably be fine, but it's not designed to be used that way intentionally, so your results ... are probably as-yet untested. I don't want to go on. This list could go on forever. I will strongly encourage you to simply use "zfs send | zfs receive" because that's a standard practice thing to do. It is known that the external drive is not bootable this way, but that's why you have this article on how to make it bootable: http://docs.sun.com/app/docs/doc/819-5461/ghzur?l=en&a=view > This would have the added benefit of the USB drive being bootable. By default, AFAIK, that's not correct. When you mirror rpool to another device, by default the 2nd device is not bootable, because it's just got an rpool in there. No boot loader. Even if you do this mirror idea, which I believe will be slower and less reliable than "zfs send | zfs receive" you still haven't gained anything as compared to the "zfs send | zfs receive" procedure, which is known to work reliable with optimal performance. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
