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Sun, 23 Dec 2018 01:55:02 +0100 Subject: Re: Specifying block group size To: Raymond Jennings , Hugo Mills , linux-btrfs@vger.kernel.org References: <20181222180438.GG30713@carfax.org.uk> From: Qu Wenruo Openpgp: preference=signencrypt Autocrypt: addr=quwenruo.btrfs@gmx.com; prefer-encrypt=mutual; keydata= mQENBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAG0IlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT6JAVQEEwEIAD4CGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCWdWCnQUJCWYC bgAKCRDCPZHzoSX+qAR8B/94VAsSNygx1C6dhb1u1Wp1Jr/lfO7QIOK/nf1PF0VpYjTQ2au8 ihf/RApTna31sVjBx3jzlmpy+lDoPdXwbI3Czx1PwDbdhAAjdRbvBmwM6cUWyqD+zjVm4RTG rFTPi3E7828YJ71Vpda2qghOYdnC45xCcjmHh8FwReLzsV2A6FtXsvd87bq6Iw2axOHVUax2 FGSbardMsHrya1dC2jF2R6n0uxaIc1bWGweYsq0LXvLcvjWH+zDgzYCUB0cfb+6Ib/ipSCYp 3i8BevMsTs62MOBmKz7til6Zdz0kkqDdSNOq8LgWGLOwUTqBh71+lqN2XBpTDu1eLZaNbxSI ilaVuQENBFnVga8BCACqU+th4Esy/c8BnvliFAjAfpzhI1wH76FD1MJPmAhA3DnX5JDORcga CbPEwhLj1xlwTgpeT+QfDmGJ5B5BlrrQFZVE1fChEjiJvyiSAO4yQPkrPVYTI7Xj34FnscPj /IrRUUka68MlHxPtFnAHr25VIuOS41lmYKYNwPNLRz9Ik6DmeTG3WJO2BQRNvXA0pXrJH1fN GSsRb+pKEKHKtL1803x71zQxCwLh+zLP1iXHVM5j8gX9zqupigQR/Cel2XPS44zWcDW8r7B0 q1eW4Jrv0x19p4P923voqn+joIAostyNTUjCeSrUdKth9jcdlam9X2DziA/DHDFfS5eq4fEv ABEBAAGJATwEGAEIACYWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCWdWBrwIbDAUJA8JnAAAK CRDCPZHzoSX+qA3xB/4zS8zYh3Cbm3FllKz7+RKBw/ETBibFSKedQkbJzRlZhBc+XRwF61mi f0SXSdqKMbM1a98fEg8H5kV6GTo62BzvynVrf/FyT+zWbIVEuuZttMk2gWLIvbmWNyrQnzPl mnjK4AEvZGIt1pk+3+N/CMEfAZH5Aqnp0PaoytRZ/1vtMXNgMxlfNnb96giC3KMR6U0E+siA 4V7biIoyNoaN33t8m5FwEwd2FQDG9dAXWhG13zcm9gnk63BN3wyCQR+X5+jsfBaS4dvNzvQv h8Uq/YGjCoV1ofKYh3WKMY8avjq25nlrhzD/Nto9jHp8niwr21K//pXVA81R2qaXqGbql+zo Message-ID: Date: Sun, 23 Dec 2018 08:54:56 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.3 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="3W4W2kEzOUgeXEmQxytDirPBeXzLdUhiF" X-Provags-ID: V03:K1:P3d21a5hOms0hhEKopynD+xMccS/AtH83sKGVnjXOkkW9j5AeRs 6qUHXw+Lrq37h+mqg/JgVvvkWik4d2gk+MmSP04OVHRKnUIYjadgkbEbV8hAZynCBntFujL lDpHxCpEln0bqAMKCjFA0+TUhyAQPgm5D4QV1EalNPWQq7TjcU7Wst128Nzx+6FuPB/x+CS 0slz2edBQVFEzLkipzI4g== X-UI-Out-Filterresults: notjunk:1;V03:K0:hX3uwtQ03Y0=:wrfixUlwRLMih2Bgr3vkm0 CTnEbGTBYm1Iobi5oisiJDqEO23OWZBhwR9BWgG3P527N0QmAoPnCFnWrFej0PoEMB4C+LuNj 5oYsGwj9cdEYTYBLx5IxUK70P7mjjidvsrdq+kE+t+83QnE/9v90PU5rJcRbpLu6Gqfpy/k1I njjJXrepp3hwwfa1MbKq6iOWfAJ7CxdugvpR6OYZVHv1ATZP5OP018vIQmp2epAihonvCfA2j VySlDxp9zOJnZnWDqZZTPpraweddwxGnUOxNwmbHsQ8DGk2KtI6otqdC907hWucTR48kgHqKB 1JYTSm/WAw4lYlcbow7tBYJ5+ZujH0HjzMy+SQdwr+10krV3HCNeMZlW0YvKy1fzl7Ceag+DK cvSOLE8F3JxGuWRPPSFOjPRJzsXr6qKmdbJ9pUmnBJY3p7b9haBp8DYE1BvR8yACnFHh9wbJi Xxl1zc8Pfn4R6ZtiDVPy8cX+yPHBw5oZxk83stvnk2UgyZTFVKRzYiB/FyP1YwLtLRRCn1IV1 exgHjSsT9jRZjT3Dm7uFSNfxCdMEkD9m2W4/Emhm1/f6wo/ra5ZtNWZbmKT0pgfr/g8b8UCUo lXkh9F99hZ/L95kQZtrsoGgksne91l1rlr/cE7cMbVWea3ZDjSyMk9IlIRxV21YQ2vBwEYTfE gKau6yEufPTEjztMQgTbhkrpPP99rZYZDCtKyue7Z7bQk+L07XoAzZZelOmKqB1Nxru9JjJpv aRpriHYAD654dlPjNQclmwXdAN6HSgDRrMkWfY77MY4i9rPNQjkgX9V7Bev8cvGaPjcpCD3qB 0eLwglEAOH0Z3RZvjU4tHpUXoFmuRUGY0NaNjoB/qsC87KO8/hra5N9uNYvTI+7KEqVIvkJjc f7NINrKrZu7oHpjnPjbszPTDuzdMZcYi1asXxOc1AMjRh5v5aq+GZnSuOOf9qG Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --3W4W2kEzOUgeXEmQxytDirPBeXzLdUhiF Content-Type: multipart/mixed; boundary="9uj3eUyW9LOvLRUEHw1aQpJozcAxATFZj"; protected-headers="v1" From: Qu Wenruo To: Raymond Jennings , Hugo Mills , linux-btrfs@vger.kernel.org Message-ID: Subject: Re: Specifying block group size References: <20181222180438.GG30713@carfax.org.uk> In-Reply-To: --9uj3eUyW9LOvLRUEHw1aQpJozcAxATFZj Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2018/12/23 =E4=B8=8A=E5=8D=882:11, Raymond Jennings wrote: > If the filesystem is later resized, does the (default?) chunk size > adjust accordingly? It depends. Btrfs calculates chunk size based on total rw bytes (no more than 10%) and clamp it to maximum chunk size (1G for normal data, 10G data for large fs, 256 for metadata and 1G data for large fs). So if you're hitting maximum chunk size already, then it will not change.= But if you're hitting 10% limit, then it will change. Despite that, raid profile and some other factors will also affect the chunk size. E.g. RAID5 with 12 disks could break the 1G/10G data chunk size limit. Thanks, Qu >=20 > On Sat, Dec 22, 2018 at 10:04 AM Hugo Mills wrote:= >> >> On Fri, Dec 21, 2018 at 10:18:40PM -0800, Raymond Jennings wrote: >>> How do I specify the size of a block group at mkfs? >> >> You don't -- there's no explicit control over it. The FS will >> decide based on the overall size of the filesystem in question. >> >> Typically, data groups are made of 1 GiB chunks, and metadata >> groups are made of 256 MiB chunks (where the RAID level will determine= >> the number of chunks in a group and the amount of usable space of the >> group). >> >> Hugo. >> >>> >>> Like, for example, saying that data groups will be 1GiB, but metadata= >>> groups will be 1MiB? >>> >>> I noticed that they had different default sizes based on the profile >>> (dup vs single vs raid) >> >> -- >> Hugo Mills | Beware geeks bearing GIFs >> hugo@... carfax.org.uk | >> http://carfax.org.uk/ | >> PGP: E2AB1DE4 | --9uj3eUyW9LOvLRUEHw1aQpJozcAxATFZj-- --3W4W2kEzOUgeXEmQxytDirPBeXzLdUhiF Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAlwe3OAACgkQwj2R86El /qhnhwf/YpiNo8qtdfQxoDl12VGIA92qxXO0cFeFLjDUp9gh4ItX6Lmjwg6v56M7 rXuzm9Fh8k509k5Q977NJaPXLD4BiJFcgKYLMP+MJ4kKeGzAqnRGgMLzz55ilnYq /LKxzJiyr1y+1TizzA11T7Pa8FJoMarKXu0R5f6DPsqQp1GCQwf+Fx7c39G+FGV9 StBB5eGDrF7mwqLVj+TSud97nKXuxE7VVI3m5u3S4vH8PY8RA/4XR5s9Uir9XsV0 WLr2tmn1lifz8n5dZLy/jX09L1Gk2Ti7Rhtowzaf8Rmmm0QL9KT/Ajtx/rOdaTiS qbNYGTh1rN/4fmcKSczR8u/PA5INqA== =gwnC -----END PGP SIGNATURE----- --3W4W2kEzOUgeXEmQxytDirPBeXzLdUhiF--