Date: Tue, 16 May 2017 08:39:36 +0100 From: Matthew Seaman <matthew@FreeBSD.org> To: freebsd-questions@freebsd.org Subject: Re: ZFS root on single SSD? Message-ID: <99fa2537-9fb1-0ccf-d906-39db1c2e2685@FreeBSD.org> In-Reply-To: <CAEsW2o88qA_YGxHC%2B5nWsi90yJfXKkCSV7tACstK6_hLNgu4HQ@mail.gmail.com> References: <CAEsW2o88qA_YGxHC%2B5nWsi90yJfXKkCSV7tACstK6_hLNgu4HQ@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --tTlkTI13EKqu1iV41QAeXuuv951kLg7Ut Content-Type: multipart/mixed; boundary="LWTT1Cb8DXvl2keGw3NiOSXjilQuP3t2F"; protected-headers="v1" From: Matthew Seaman <matthew@FreeBSD.org> To: freebsd-questions@freebsd.org Message-ID: <99fa2537-9fb1-0ccf-d906-39db1c2e2685@FreeBSD.org> Subject: Re: ZFS root on single SSD? References: <CAEsW2o88qA_YGxHC+5nWsi90yJfXKkCSV7tACstK6_hLNgu4HQ@mail.gmail.com> In-Reply-To: <CAEsW2o88qA_YGxHC+5nWsi90yJfXKkCSV7tACstK6_hLNgu4HQ@mail.gmail.com> --LWTT1Cb8DXvl2keGw3NiOSXjilQuP3t2F Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable On 16/05/2017 06:45, Aaron wrote: > So, I've been running ZFS root mirror across 2 spinning disks, and I'm > upgrading my home server/nas and planning on running root on a spare SS= D. > However, I'm unsure if it'd be better to run UFS as a single drive root= > instead of ZFS, although I do love all of the ZFS features (snapshots, = COW, > scrubbing, etc) and would still like to keep that for my root drive, ev= en > if I'm not mirroring at all. I do notice that FreeBSD has TRIM support = for > ZFS (see http://open-zfs.org/wiki/Features#TRIM_Support). >=20 > So is there a good reason NOT to run ZFS root on a single drive SSD? No. Running ZFS on a single device works fine, although you obviously don't benefit from all the really nice resilience features. The choice between UFS2 and ZFS basically comes down to three points: * performance -- for certain IO patterns, UFS can out-perform ZFS quite markedly. Particularly the sort of small, randomly distributed IOs you get with a RDBMS. Of course, for database use, the additional data security you get from ZFS makes it desirable despite this. * system resources -- ZFS is memory hungry. This is not a problem on most contemporary machines, which tend to have sufficient RAM, but older machines, VMs or appliances may struggle. * data security -- the integrated checksumming in ZFS provides assurance that the data you're reading now is the same as what you wrote previously. Now, this is almost always the case with UFS2 (would be entirely useless if not), but there is no actual guarantee of it, and silent data corruption is possible[*]. If you're handling data which is really important or in particularly large volumes or where your hardware may prove deficient, then ZFS is indicated. Cheers, Matthew [*] With only one drive and one copy of each file, ZFS cannot provide resilience against data errors, but it will prevent it going unnoticed. --LWTT1Cb8DXvl2keGw3NiOSXjilQuP3t2F-- --tTlkTI13EKqu1iV41QAeXuuv951kLg7Ut Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQJ8BAEBCgBmBQJZGqzAXxSAAAAAAC4AKGlzc3Vlci1mcHJAbm90YXRpb25zLm9w ZW5wZ3AuZmlmdGhob3JzZW1hbi5uZXQ2NTNBNjhCOTEzQTRFNkNGM0UxRTEzMjZC QjIzQUY1MThFMUE0MDEzAAoJELsjr1GOGkATAhEP/2UKQ4xgF94vpiMjQJdCsK9x 2e/wq2mIhNFLpeXHLsiRma/RN0mcvOFfhCj5zPZvvsrCZoyKZf2cPq8UR1r6aYPx bd//fHlvQIDKIBsA9GzH8R6q9nZ/xVkSSbS63tAiAETY3DqQg6Zl+BgJloxN4S35 ibKfBsQGRuCYBLjcbgShoJvdYeOWv+q0nApm62dvbjGDh7ufbQMejxMPyPnV1j6M PWoda35MfpDy2isJho5M5CsUDD4qoPprvNZ/J0hP3gsCZzifuZULvf1aCJrfEf8f W9so8ERWiQ6r/E7PwnJpgFhSEhM50haHrnyMlgzWmxvTY01KbiXRuE5RZP2X6zJi tawhcFISe0aoK0kfoizMOGcEemmzJ6GgbYPGwAm5IsH5gSrxRMIELHUJ3t31Xvc6 SBedV93QU7ckvqDSqldpc6ORhtVAIbuuZSQ1q19fzBwnvjxqfExsMy4suLDtWpow gbsE/OAL0VN2A5iV4KD64YLA4PXxPiTd3ivQXRjhBgSwiPN+lZ9JQLsQE36R8wKO 0UCUS32ltVfUAIH/IV0DHGZvoH99afCsEe2m14UgP/6BJMkc0Jw1KgiJdCjbmDqM Q+cjfZv167xglrAU8Jke6rvW+J1QbcABonupq5MwGT7KR6W0/MJ1ii1mmxAVzLnu +L4TIfaDgzKwDnd53doN =aFj0 -----END PGP SIGNATURE----- --tTlkTI13EKqu1iV41QAeXuuv951kLg7Ut--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?99fa2537-9fb1-0ccf-d906-39db1c2e2685>