Date: Sat, 28 Aug 2021 12:03:05 +1000 From: Peter Jeremy <peter@rulingia.com> To: Alan Somers <asomers@freebsd.org> Cc: George Michaelson <ggm@algebras.org>, Ben RUBSON <ben.rubson@gmx.com>, freebsd-fs <freebsd-fs@freebsd.org> Subject: Re: ZFS on high-latency devices Message-ID: <YSmZWfo51Okan5QY@server.rulingia.com> In-Reply-To: <CAOtMX2hRuh_9ZOOoQufNT2QG3Ui0S3rJq%2BL-ox2kxsq1oJMSMA@mail.gmail.com> References: <YR4mY%2Bb6o7fBJqEN@server.rulingia.com> <023225AD-2A97-47C5-9FE4-3ABF1BFD66F1@gmx.com> <CAKr6gn0r8xG9HNGOFh1A_usU4tPAYezeZv1chOG_bBMqy_HtXw@mail.gmail.com> <CAOtMX2hRuh_9ZOOoQufNT2QG3Ui0S3rJq%2BL-ox2kxsq1oJMSMA@mail.gmail.com>
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[-- Attachment #1 --] On 2021-Aug-22 17:48:13 -0600, Alan Somers <asomers@freebsd.org> wrote: >mbuffer is not going to help the OP. I agree that mbuffer won't help. I already use something equivalent to remove the read latency on the send side. >And if I understand correctly, he's >connecting over a WAN, not a LAN. ZFS will never achieve decent >performance in such a setup. It's designed as a local file system, and >assumes it can quickly read metadata off of the disks at any time. Yes. But, at least with a relatively empty destination, zfs actually does almost no reads whilst doing a recv. As far as I can tell, the problem is that zfs does a complete flush of all data and metadata at snapshot boundaries. This is painful even with local filesystems (it typically takes >1s to recv an empty snapshot with local disks). >The >OP's best option is to go with "a": encrypt each dataset and send them with >"zfs send --raw". I don't know why he thinks that it would be "very >difficult". It's quite easy, if he doesn't care about old snapshots. Just: I agree that "zfs send --raw" is the best solution to network RTT and I agree that migrating to ZFS native encryption is quite easy if you don't care about any ZFS features. However, I do care about old snapshots - migrating to ZFS native encryption is a non-starter if it involves throwing away all my old snapshots and clones. I have also been working on migrating to native encryption. I know how to migrate snapshots and think there a way to migrate clones (but I need to validate it). The remaining definite blocker is working out how to migrate the pool root filesystem (including snapshots). -- Peter Jeremy [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEE7rKYbDBnHnTmXCJ+FqWXoOSiCzQFAmEpmVNfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldEVF QjI5ODZDMzA2NzFFNzRFNjVDMjI3RTE2QTU5N0EwRTRBMjBCMzQACgkQFqWXoOSi CzRr7hAAmb3w4XGMgHuPi97RlWZcYahErnCaYB+ROGs2pJLRUVJQyTDGxBQqVVJ8 AEiNYtMwdCqtj9WI42klYuJQB5tO4IhByKulcDs8oqzeUSJW2IVeqRiMfqxJMyuk 74XHBLiDCZyy6+U4d/Bh6YIWQZpXsZXNUFJ+GcKy/1Y0ciyPAjeugRXzxpj5+Wg3 PaXC2zOnlipWSbHI9966JsKn/2yIXIsPQadfIhBy0KsdlXGdRq2mGVkgmaXpLBJD nxdN+fY/6ighFRuc4orh2RY4HOIpRPnWGYpG4MBAjTB2CskrgpSRxms2vYsoOaYq hJOe6t5BjWehh+cC3aq86Z9M15ceaogIk+D9D6okOOsOUBJfCfDUoNmlzAhZAZpp YEfp1tiToPKvBtccWAsIs8qoxp9aaChuwl6qxpELIg6e/U/FdpWV2R4xJYuzUIW5 CW8ArFLm28yRYSNvfNiylJQrwK9dZSUSWTGD4mUlU4Nt3/Sil5nAsvdZ1i530lNZ PUWuxlqO47sa2bUamvP/Tua6WOxhF0boNMaX6d4iPuf/X+S8yhOBbl/uvYAFD7Di ZKKbdA8yjzf46mLVeZy0UFytkf61InDDlkGIiXaQA+RNCqu4Tm8mGI6vEh0C3EMt SwcmG+ooxWJTfdIF1lTDHcGrHho8zklbBgQJWWD0e+NNagEMcHg= =hLr9 -----END PGP SIGNATURE-----
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