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diff --git a/static/freebsd/man4/md.4 3.html b/static/freebsd/man4/md.4 3.html deleted file mode 100644 index bc3401aa..00000000 --- a/static/freebsd/man4/md.4 3.html +++ /dev/null @@ -1,143 +0,0 @@ -<table class="head"> - <tr> - <td class="head-ltitle">MD(4)</td> - <td class="head-vol">Device Drivers Manual</td> - <td class="head-rtitle">MD(4)</td> - </tr> -</table> -<div class="manual-text"> -<section class="Sh"> -<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1> -<p class="Pp"><code class="Nm">md</code> — <span class="Nd">memory - disk</span></p> -</section> -<section class="Sh"> -<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1> -<p class="Pp">To compile this driver into the kernel, place the following lines - in your kernel configuration file:</p> -<div class="Bd Pp Bd-indent"><code class="Cd">device md</code></div> -<p class="Pp">Alternatively, to load the driver as a module at boot time, place - the following line in <a class="Xr">loader.conf(5)</a>:</p> -<div class="Bd Pp Bd-indent Li"> -<pre>geom_md_load="YES"</pre> -</div> -</section> -<section class="Sh"> -<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1> -<p class="Pp">The <code class="Nm">md</code> driver provides support for four - kinds of memory backed virtual disks:</p> -<dl class="Bl-tag"> - <dt id="malloc"><a class="permalink" href="#malloc"><code class="Cm">malloc</code></a></dt> - <dd>Backing store is allocated using <a class="Xr">malloc(9)</a>. Only one - malloc-bucket is used, which means that all <code class="Nm">md</code> - devices with <code class="Cm">malloc</code> backing must share the - malloc-per-bucket-quota. The exact size of this quota varies, in - particular with the amount of RAM in the system. The exact value can be - determined with <a class="Xr">vmstat(8)</a>.</dd> - <dt id="preload"><a class="permalink" href="#preload"><code class="Cm">preload</code></a></dt> - <dd>A module loaded by <a class="Xr">loader(8)</a> with type - ‘md_image’ is used for backing store. For backwards - compatibility the type ‘mfs_root’ is also recognized. See - the description of module loading directives in - <a class="Xr">loader.conf(5)</a> and note that the module name will either - be an absolute path to the image file or the name of a file in the - <var class="Va">module_path</var>. - <p class="Pp">If the kernel is created with option - <code class="Dv">MD_ROOT</code> the first preloaded image found will - become the root file system.</p> - </dd> - <dt id="vnode"><a class="permalink" href="#vnode"><code class="Cm">vnode</code></a></dt> - <dd>A regular file is used as backing store. This allows for mounting ISO - images without the tedious detour over actual physical media.</dd> - <dt id="swap"><a class="permalink" href="#swap"><code class="Cm">swap</code></a></dt> - <dd>Backing store is allocated from buffer memory. Pages get pushed out to the - swap when the system is under memory pressure, otherwise they stay in the - operating memory. Using <code class="Cm">swap</code> backing is generally - preferable over <code class="Cm">malloc</code> backing.</dd> -</dl> -<p class="Pp">For more information, please see - <a class="Xr">mdconfig(8)</a>.</p> -</section> -<section class="Sh"> -<h1 class="Sh" id="EXAMPLES"><a class="permalink" href="#EXAMPLES">EXAMPLES</a></h1> -<p class="Pp">To create a kernel with a ramdisk or MD file system, your kernel - config needs the following options:</p> -<div class="Bd Pp Bd-indent Li"> -<pre>options MD_ROOT # MD is a potential root device -options MD_ROOT_READONLY # disallow mounting root writeable -options MD_ROOT_SIZE=8192 # 8MB ram disk -makeoptions MFS_IMAGE=/h/foo/ARM-MD -options ROOTDEVNAME=\"ufs:md0\"</pre> -</div> -<p class="Pp">The image in <span class="Pa">/h/foo/ARM-MD</span> will be loaded - as the initial image each boot. To create the image to use, please follow - the steps to create a file-backed disk found in the - <a class="Xr">mdconfig(8)</a> man page. Other tools will also create these - images, such as NanoBSD.</p> -</section> -<section class="Sh"> -<h1 class="Sh" id="ARM_KERNEL_OPTIONS"><a class="permalink" href="#ARM_KERNEL_OPTIONS">ARM - KERNEL OPTIONS</a></h1> -<p class="Pp">On the armv7 architecture, an MD_ROOT image larger than - approximately 55 MiB may require building a custom kernel using several - tuning options related to kernel memory usage.</p> -<dl class="Bl-tag"> - <dt><code class="Cd">options LOCORE_MAP_MB=<num></code></dt> - <dd>This configures how much memory is mapped for the kernel during the early - initialization stages. The value must be at least as large as the kernel - plus all preloaded modules, including the root image. There is no downside - to setting this value too large, as long as it does not exceed the amount - of physical memory. The default is 64 MiB.</dd> - <dt><code class="Cd">options NKPT2PG=<num></code></dt> - <dd>This configures the number of kernel L2 page table pages to preallocate - during kernel initialization. Each L2 page can map 4 MiB of kernel space. - The value must be large enough to map the kernel plus all preloaded - modules, including the root image. The default value is 32, which is - sufficient to map 128 MiB.</dd> - <dt><code class="Cd">options VM_KMEM_SIZE_SCALE=<num></code></dt> - <dd>This configures the amount of kernel virtual address (KVA) space to - dedicate to the kmem_arena map. The scale value is the ratio of physical - to virtual pages. The default value of 3 allocates a page of KVA for each - 3 pages of physical ram in the system. The kernel and modules, including - the root image, also consume KVA. The combination of a large root image - and the default scaling may preallocate so much KVA that there is not - enough remaining address space to allocate kernel stacks, IO buffers, and - other resources that are not part of kmem_arena. Overallocating kmem_arena - space is likely to manifest as failure to launch userland processes with - "cannot allocate kernel stack" messages. Setting the scale value - too high may result in kernel failure to allocate memory because - kmem_arena is too small, and the failure may require significant runtime - to manifest. Empirically, a value of 5 works well for a 200 MiB root image - on a system with 2 GiB of physical ram.</dd> -</dl> -</section> -<section class="Sh"> -<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE - ALSO</a></h1> -<p class="Pp"><a class="Xr">gpart(8)</a>, <a class="Xr">loader(8)</a>, - <a class="Xr">mdconfig(8)</a>, <a class="Xr">mdmfs(8)</a>, - <a class="Xr">newfs(8)</a>, <a class="Xr">vmstat(8)</a></p> -</section> -<section class="Sh"> -<h1 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h1> -<p class="Pp">The <code class="Nm">md</code> driver first appeared in - <span class="Ux">FreeBSD 4.0</span> as a cleaner replacement for the MFS - functionality previously used in PicoBSD and in the - <span class="Ux">FreeBSD</span> installation process.</p> -<p class="Pp" id="vn">The <code class="Nm">md</code> driver did a hostile - takeover of the <a class="permalink" href="#vn"><b class="Sy">vn</b></a> - driver in <span class="Ux">FreeBSD 5.0</span>.</p> -</section> -<section class="Sh"> -<h1 class="Sh" id="AUTHORS"><a class="permalink" href="#AUTHORS">AUTHORS</a></h1> -<p class="Pp">The <code class="Nm">md</code> driver was written by - <span class="An">Poul-Henning Kamp</span> - <<a class="Mt" href="mailto:phk@FreeBSD.org">phk@FreeBSD.org</a>>.</p> -</section> -</div> -<table class="foot"> - <tr> - <td class="foot-date">July 16, 2025</td> - <td class="foot-os">FreeBSD 15.0</td> - </tr> -</table> |