From owner-freebsd-questions@FreeBSD.ORG Wed Aug 6 07:32:57 2014 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 474644F4 for ; Wed, 6 Aug 2014 07:32:57 +0000 (UTC) Received: from sdf.lonestar.org (mx.sdf.org [192.94.73.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mx.sdf.org", Issuer "SDF.ORG" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 1C5872EAE for ; Wed, 6 Aug 2014 07:32:56 +0000 (UTC) Received: from sdf.org (IDENT:bennett@sdf.lonestar.org [192.94.73.15]) by sdf.lonestar.org (8.14.8/8.14.5) with ESMTP id s767Wl7C011454 (using TLSv1/SSLv3 with cipher DHE-RSA-AES256-GCM-SHA384 (256 bits) verified NO) for ; Wed, 6 Aug 2014 07:32:47 GMT Received: (from bennett@localhost) by sdf.org (8.14.8/8.12.8/Submit) id s767WlPP027322 for freebsd-questions@freebsd.org; Wed, 6 Aug 2014 02:32:47 -0500 (CDT) From: Scott Bennett Message-Id: <201408060732.s767WlPP027322@sdf.org> Date: Wed, 06 Aug 2014 02:32:47 -0500 To: freebsd-questions@freebsd.org Subject: some ZFS questions User-Agent: Heirloom mailx 12.4 7/29/08 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 06 Aug 2014 07:32:57 -0000 I have a number of questions that I need answered before I go about setting up any raidz pools. They are in no particular order. 1) What is the recommended method of using geli encryption with ZFS? Does one first create .eli devices and then specify those .eli devices in the zpool(8) command as the devices to include in the pool? Or is there some way to create the pool first and then encrypt the pool? Or maybe "zfs create -V size volname" and then "geli init /dev/zvol/volname" and "newfs /dev/zvol/volname.eli"? 2) How does one start or stop a pool? From what I've read, it appears that ZFS automatically starts all the pools at once. If there is a problem after a crash that causes ZFS to decide to run some sort of repairs without waiting for a go-ahead from a human, ZFS might create still more problems. For example, if a set of identically partitioned drives has a pool made of one partition from each drive and another pool made from a different set of partitions, a rebuild after a failed/corrupted drive might start on both pools at once, thereby hammering all of the drives mercilessly until something else, hardware or software, failed. Having a way to allow one to complete before starting another would be critical in such a configuration. Also, one might need stop a pool in order to switch hardware connections around. I see the zpool(8) command has a "reopen" command, but I don't see a "close" counterpart, nor a description of when a "reopen" might be used. 3) If a raidz2 or raidz3 loses more than one component, does one simply replace and rebuild all of them at once? Or is it necessary to rebuild them serially? In some particular order? 4) At present, I'm running 9-STABLE i386. The box has 4 GB of memory, but the kernel ignores a bit over 1 GB of it. The ZFS documentation recommends building a kernel with "options KVA_PAGES=512" for use with ZFS. What impact would that have on the rest of my system? Would the default, which is in my currently running kernel as modified from GENERIC, suffice for low- intensity use until I can upgrade to amd64? (Low-intensity here means copying the data from other file systems into the pools, followed by occasional reading or writing. I am currently the only human user. The machine is mostly used for number crunching and as a tor relay.) 5) When I upgrade to amd64, the usage would continue to be low- intensity as defined above. Will the 4 GB be enough? I will not be using the "deduplication" feature at all. 6) I have a much fancier computer sitting unused that I intend to put into service fairly soon after getting my current disk and data situation resolved. The drives that would be in use for raidz pools I would like to attach to that system when it is ready. It also has 4 GB of memory, but would start out as an amd64 system and might well have another 2 GB or 4 GB added at some point(s), though not immediately. What problems/pitfalls/precautions would I need to have in mind and be prepared for in order to move those drives from the current system to that newer one? Depending upon the answers to the above, I may well have further questions, but those are the most worrisome to me at the moment. Any information/suggestions would be most welcome. Thanks much in advance for any you can offer. Scott Bennett, Comm. ASMELG, CFIAG ********************************************************************** * Internet: bennett at sdf.org *xor* bennett at freeshell.org * *--------------------------------------------------------------------* * "A well regulated and disciplined militia, is at all times a good * * objection to the introduction of that bane of all free governments * * -- a standing army." * * -- Gov. John Hancock, New York Journal, 28 January 1790 * **********************************************************************