Date: Fri, 22 Jul 2016 15:10:00 -0500 From: "Eric A. Borisch" <eborisch@gmail.com> To: Karl Denninger <karl@denninger.net> Cc: "freebsd-fs@freebsd.org" <freebsd-fs@freebsd.org> Subject: Re: ZFS, SSD and encryption Message-ID: <CAASnNnq34crTVMoqkUhqhccYkajDT=grfMKaeWQB466P78BJOw@mail.gmail.com> In-Reply-To: <c52ebaa8-e82b-1a17-d868-52c40032c3d5@denninger.net> References: <CAJPDrRtLBNKr4BynSGMRfFGdAR0ZbDuwfcqkLupvk5HtgqrbQg@mail.gmail.com> <b8b000ff-289c-7348-8b63-00f3ac51accf@denninger.net> <CAASnNnpnST%2BD6fVT%2BFrH%2BomkwNQb4rG1NJk0T=O2AetzrXEThA@mail.gmail.com> <c52ebaa8-e82b-1a17-d868-52c40032c3d5@denninger.net>
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On Fri, Jul 22, 2016 at 2:27 PM, Karl Denninger <karl@denninger.net> wrote: > On 7/22/2016 14:02, Eric A. Borisch wrote: >> On Friday, July 22, 2016, Karl Denninger <karl@denninger.net >> <mailto:karl@denninger.net>> wrote: >> >> >> On 7/22/2016 07:48, Nikos Kastanas wrote: >> > I have a Lenovo X220 laptop running FreeBSD 10.3-RELEASE with >> ZFS and >> > encryption on a plain HDD. I am considering buying a Samsung Pro >> 850 SSD to >> > boost performance but I am not sure if TRIM and ZFS+Encryption >> work well >> > together. After some research online, I found *this page* >> > <https://www.freebsd.org/doc/faq/all-about-zfs.html>which states the >> > following: >> > >> > *Note: * >> > ZFS TRIM may not work with all configurations, such as a ZFS >> filesystem on >> > a GELI-backed device. >> > >> > From what I can understand from the above note, I should not use the >> > encryption option when installing FreeBSD with ZFS on an SSD. >> TRIM will not >> > work correctly and therefore the SSD performace will be impacted. >> Meh. Simply not true. >> >> >> It will not work on 10.3, but will work (as Karl demonstrates) on >> 11.x. Here's the commit to head enabling it: >> >> https://svnweb.freebsd.org/base?view=revision&revision=286444 >> >> And here's what is in 10.3 (BIO_DELETE case returns EOPNOTSUPP): >> >> https://svnweb.freebsd.org/base/releng/10.3/sys/geom/eli/g_eli.c?revision=296373&view=markup#l319 >> >> - Eric > > Note that the system in question (from which the stats were pulled) was > on 10.2 for an extended period of time, with SSDs, and with > Geli-encrypted disks. It was fine with no performance issues; whether > there is a problem with earlier releases has much to do with the disks > in question. > > In the case of the Intel 730s it works perfectly well even though TRIM > is not passed through in that case. Fair, but the original question was if "TRIM will not work correctly and therefore the SSD performace will be impacted" -- and the answer is that TRIM+GELI does not "work correctly" for 10.3, but it does for 11.x. This is only a performance (and not "is my data safe") statement. As you allude to, how much this impacts performance depends on the drive, partitioning / provisioning, and workload. - Eric
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