Date: Mon, 24 Nov 2014 07:16:04 +0000 From: Matthew Seaman <m.seaman@infracaninophile.co.uk> To: freebsd-questions@freebsd.org Subject: Re: How much space does raidz2 'eat'? Message-ID: <5472DB34.8080500@infracaninophile.co.uk> In-Reply-To: <20141123232623.39d46c80@falbala.rz1.convenimus.net> References: <20141123232623.39d46c80@falbala.rz1.convenimus.net>
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This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --LTps0rBjdrP9MMQNA7Gx5AEvIpGkLU7Fs Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 23/11/2014 22:26, Christian Baer wrote: > After creating a raidz2 pool, I get this: > Now I know that while WD works with kB, FreeBSD works with KiB (factor > 1024). However, if I break this drive down to that and multiply that by= > 5, I get 18.19TiB, while df gives me 16TiB. Sure, there is some > overhead and all, but certainly (hopefully) not 2 whole TiB! That would= > be more than 10%. Use 'zpool list' to see the actual size and usage of your pool. The amount you lose in overhead from partitioning and setting up geli providers is pretty neglible; it's all down Yes, RAIDZ2 has around that level of overhead: think two parity blocks for each three data blocks, so worst case is that about 40% of your raw space will disappear. The actual amount depends on exactly how many drives you're using. > Is this normal or am I missing something? See: http://blog.delphix.com/matt/2014/06/06/zfs-stripe-width/ Cheers, Matthew --=20 Dr Matthew J Seaman MA, D.Phil. PGP: http://www.infracaninophile.co.uk/pgpkey JID: matthew@infracaninophile.co.uk --LTps0rBjdrP9MMQNA7Gx5AEvIpGkLU7Fs Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.20 (Darwin) iQJ8BAEBCgBmBQJUcts8XxSAAAAAAC4AKGlzc3Vlci1mcHJAbm90YXRpb25zLm9w ZW5wZ3AuZmlmdGhob3JzZW1hbi5uZXQ2NTNBNjhCOTEzQTRFNkNGM0UxRTEzMjZC QjIzQUY1MThFMUE0MDEzAAoJELsjr1GOGkATL2wP/0tNlPlQ2yjkmBaoTn2tvD2v FXU2DJPlxXoG+tAg7jhNIKSdFBwKsDElhWM/7yKKjW+BDfU869vT11rs4co6HbAl S3G19FYegdLRzVKKlSBF80i2ApUAfc2HdvrAaOL1jN0608pBRFIeTCZNVg5Gukig dbKIC1Yxh2HiQy8c7t09m71q16H5nR7ZA/Itm/AVlKM7xa7Q4Tf9ZWvrX0cqwlwS 60c93cX8oI03UhTwAAnbcXYMHxE/6385LDCuUkm8ZBb2Y4X6GxU+G7RYWe2m2WRm 19gJgtQdXaocL2RdZ1yqXY+NUNBofh0XBU8atR/q8SM4OUB7yMGJZ9APwaRPaYwO a8nzT0t4UmVrqIubTHqNGqLaChZQbLyAbCjv4Bku2ZnbL2xa7LYHbwCsvPQweJPy 5u8pfVsou6awiDOlb8mnhGiIO/38f+dLD8wR97WsSOnLgs/5G9tQ2vLW7GGwL5J2 yUu/rF/54ZY80+fBt/VCff0diXDmk7Wq5n6lVF+6hvC2tPYj1Viqhk5CgtAtPc8b 29bj80Dm1p8FaykJtrFvzRnhMCvLuaLUF4MmNvx2aLUFBOcr6ygw2tbYKww4jSZc cY+u9EJef3wCWbJ1YL85yn/SENkDUKXNd1S1Wy4mZMNDwcQU4caPGtgbMZrpSl4L +Ya7pBdgb4cFOLem9094 =xQYJ -----END PGP SIGNATURE----- --LTps0rBjdrP9MMQNA7Gx5AEvIpGkLU7Fs--
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