Date: Thu, 21 Aug 2014 10:26:15 -0400 From: Paul Kraus <paul@kraus-haus.org> To: Scott Bennett <bennett@sdf.org> Cc: freebsd-questions@freebsd.org Subject: Re: some ZFS questions Message-ID: <FE57A90F-8783-40E1-A3FF-08867129CFA4@kraus-haus.org> In-Reply-To: <201408211033.s7LAXWbN006985@sdf.org> References: <201408070816.s778G9ug015988@sdf.org> <53E3A836.9080904@my.hennepintech.edu> <201408080706.s78765xs022311@sdf.org> <D3447347-512D-4DFF-BC4A-8ECE5B77F3D4@kraus-haus.org> <201408211033.s7LAXWbN006985@sdf.org>
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On Aug 21, 2014, at 6:33, Scott Bennett <bennett@sdf.org> wrote: > Paul Kraus <paul@kraus-haus.org> wrote: >> How much does the geli encryption cost in terms of space and speed? = Is there a strong reason to not encrypt ALL the data? It can be in = different zfs datasets (the ZFS term for a filesystem). In fact, I am = NOT a fan of using the base dataset that is created with every zpool; I = always create addition zfs datasets below the root of the zpool. >=20 > Copying a file from one .eli partition to another can easily run = up > to 25% on each of two cores of a Q6600. > I didn't realize that there would be a "base data set"; I thought = that > one had to create at least one file system or zvol in a pool in order = to > use the space at all. When you create a zpool you get both the zpool and a zfs dataset of the = same name. You can use this dataset, but if I am going to be creating = *any* other datasets in this zpool I do not. I only use hierarchical = datasets in very specific ways as there are rules on inheritance and = mount points. For example: zpool create a <dev> gets you a mounted on /a zfs create a/b then gets you a mounted on /a=20 a/b mounted on /a/b You can then set the mount point to anything you wish, but unless you = explicitly set it on a/b, b will always be mounted just under a. I do the following: zpool create m <dev> m mounted on /m zfs set mountpoint=3Dnone m m not mounted zfs create m/n=20 m not mounted m/n not mounted zfs set mounptpoint=3D/foo m/n m not mounted m/n mounted on /foo >>> How does one set a limit? Is there an undocumented sysctl = variable >>> for it? >>=20 >> $ sysctl -a | grep vfs.zfs >>=20 >> to find all the zfs handles (not all may be tunable) >=20 > Are they all documented somewhere? I have not found documentation for them, but I also have not looked = through the source code. I am an admin and not a developer, so looking = through the source would be of limited use for me. I expect that many of = them map to the similar kernel parameters under Illumos (Solaris) and = most of those that you might want to change are documented (but I do not = recall where right now). -- Paul Kraus paul@kraus-haus.org
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