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It's interesting; I'm the kind of person who feels uncomfortable using something without understanding the shape of the stack underneath it. A magic black box i

It's interesting; I'm the kind of person who feels uncomfortable using something without understanding the shape of the stack underneath it. A magic black box is anathema; I want to know how to use the thing with mechanical sympathy, aligning my work with the grain of the implementation details. I want to understand error messages when they happen. I want to know how to diagnose something when it breaks, especially when it's something as important as my data. I like how ZFS is put together. I've been running it for about 13 years. I started with Nexenta, a Solaris fork with Debian userland. I've ported my pool twice, had a bunch of HDD failures, and haven't lost a single byte. I agree with you on most of the encryption stuff. That is very recent and not fully integrated and the user experience isn't fully baked. I don't agree on unifying zpool and zfs; for a good long time, I served zvols from my zpool, and dividing up storage management and its redundancy configuration from file system management makes sense to me. Similarly, recursive datasets make sense; you want inheritance or something very like it when managing more than a handful of filesystems. I don't agree on pool names (why anyone would want ordinal pool naming and just replicate the problem you just stated re sda, sdb etc. is a bit mysterious), and I don't agree on snapshots (to me this is like preferring commit IDs in git to branch and tag names - manually created snapshots outside periodic pruning should be named). ZoL on Ubuntu does periodic scrubs by default now. Sometimes I have to stop them because they noticeably impact I/O too much. Periodic snapshots is one of the first cronjobs I created on Nexenta, and while there's plenty of tooling, it also needs configuration - if you are not aware of it, it's an easy way to retain references to huge volumes of data, depending on use case. Not all of my ZFS filesystems are periodically snapshotted the same way.

istjohn 3y ago
I see the utility in recursive datasets and I wouldn't want them to go away, but if I were creating a zfs-for-dummies I wouldn't include the functionality. You'd have to drop down to the raw zpool/zfs commands to get that. Likewise, I appreciate being able to name snapshots, but it's annoying to have to manually name the snapshot I create in order to zfs send. The solution there is probably to not make me take a manual snapshot in the first place. `zfs send` should automatically make the snapshot for me. But in general, I don't see why zfs can't default to a generic name and let me override it with a `--name` flag. Giving it more thought, I think I would keep pool naming. What I don't like is the possibility of having pool name collisions which isn't something you have to think about with, say, ext4 filesystems. But the upshot, as you point out, is with zfs you aren't stuck using sda, sdb, etc.
- fluidcruft 3y ago
  What's the lifecycle of an automatically-created snapshot? i.e. is the snapshot garbage? How does it get collected? Things like autosnapshot implement policy to take care of itself but... zfs send one-offs? zfs send is a strange beast. It's more like differential tar than rsync (i.e. a stream intended for linear backup). zfs is cool because it unifies backup/restore. Have you tried restoring differential tar from unlabeled tapes?

istjohn 3y ago

I see the utility in recursive datasets and I wouldn't want them to go away, but if I were creating a zfs-for-dummies I wouldn't include the functionality. You'd have to drop down to the raw zpool/zfs commands to get that. Likewise, I appreciate being able to name snapshots, but it's annoying to have to manually name the snapshot I create in order to zfs send. The solution there is probably to not make me take a manual snapshot in the first place. `zfs send` should automatically make the snapshot for me. But in general, I don't see why zfs can't default to a generic name and let me override it with a `--name` flag. Giving it more thought, I think I would keep pool naming. What I don't like is the possibility of having pool name collisions which isn't something you have to think about with, say, ext4 filesystems. But the upshot, as you point out, is with zfs you aren't stuck using sda, sdb, etc.

fluidcruft 3y ago
What's the lifecycle of an automatically-created snapshot? i.e. is the snapshot garbage? How does it get collected? Things like autosnapshot implement policy to take care of itself but... zfs send one-offs? zfs send is a strange beast. It's more like differential tar than rsync (i.e. a stream intended for linear backup). zfs is cool because it unifies backup/restore. Have you tried restoring differential tar from unlabeled tapes?