Date: Fri, 23 Sep 2022 15:13:09 -0700 From: David Christensen <dpchrist@holgerdanske.com> To: questions@freebsd.org Subject: Re: zfs replication tool Message-ID: <5b4ada11-9537-f6e5-2e2b-003be7b0c355@holgerdanske.com> In-Reply-To: <3FD7D1F5-F37E-4B48-A67B-DAE9DBDD5DEA@gromit.dlib.vt.edu> References: <20220916133046.znfelln3fisrjnuz@x1> <d952d824-bcab-cfef-1b95-a8e71388c588@sentex.net> <20220916134918.hz6glg3nfwr3ouu4@x1> <0a0ba81b-88f2-fa75-9abe-6f41da5d2c69@sentex.net> <20220916140236.jeizzganrtnsrhlo@x1> <20220920092905.3k7qzt7lvhywhcfn@x1> <20220920122029.ufsoyo47qnxtmcqk@x1> <3FD7D1F5-F37E-4B48-A67B-DAE9DBDD5DEA@gromit.dlib.vt.edu>
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On 9/23/22 06:48, Paul Mather wrote: > I like zrepl on the whole but it has some annoying quirks and limitations currently that, although I use it for daily replications, make me wish these issues could be addressed: > > 1) Although you can specify a snapshot prefix for pruning purposes, zrepl selects datasets for replication. I discovered that all snapshots on those datasets are replicated, not just the ones you want stewarded by zrepl. That makes me think zrepl is using the '-I' option with 'zfs send' (e.g. incremental stream with target and all intermediary snapshots). I recently wanted just the monthly snapshots of certain datasets on a retired/ archived pool. I did it by hand, one dataset at a time. I started by replicating the oldest snapshot by itself; e.g. 'zfs send' without the '-R' option. I then did a series of 'zfs send' operations with the '-i' option (e.g. incremental stream with target only). I intend to include this use-case in my next generation homebrew scripts. > In my case, I also use Tivoli TSM (now Spectrum Protect) to back up a system, and make a snapshot (for consistency), which is backed up. (The snapshot is deleted after the backup finishes.) I found that zrepl runs were picking up this ephemeral snapshot during the pull job and then getting into a tumult ... My workflow is to start with a full replication on new backup media (e.g. large HDD). Then periodically (weekly or sooner), I do incremental replication (with '-I' option) to online media and/or near-site removable media. On a longer period (monthly), I rotate the near-site media and another off-site media. I must be careful to only destroy snapshots (live or on any backup) that are older than the oldest incremental target on any backup (e.g. three months). > 2) Related to 1) above, replicated boot environments cause problems when I delete them (which is usually after I've successfully upgraded). It leaves a dangling snapshot hold on the receiver side, which I need to clean up manually. I do not attempt to replicate my boot or root pools. I keep my OS instances small enough to fit onto a "16 GB" device and back up by taking a raw image with dd(1) (monthly, or sooner). David
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