> For the complete documentation index, see [llms.txt](https://book.bsdcn.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://book.bsdcn.org/man/man4/geom_uzip.4.md). # geom\_uzip.4 `geom_uzip` — 基于 GEOM 的压缩磁盘映像和分区 ## 名称 `geom_uzip` ## 概要 `要将本驱动程序编译进内核，请在你的内核配置文件中加入以下行：` > device xz options zstd options GEOM\_UZIP `或者，要在引导时以模块方式加载该驱动程序，请在 loader.conf(5) 中加入以下行：` ```sh geom_uzip_load="YES" ``` ## 描述 `geom_uzip` 框架提供对压缩只读磁盘映像的支持。这可以节省大量存储空间，代价是每次读取时消耗一些 CPU 时间。写入 GEOM 标签区域的数据允许 `geom_uzip` 检测通过 mkuzip(8) 创建的压缩映像，并通过 [md(4)](/man/man4/md.4.md) 将其作为逻辑磁盘设备呈现给内核。`geom_uzip` 为每个映像创建唯一的 `md#.uzip` 设备。 `geom_uzip` 不仅限于支持 [md(4)](/man/man4/md.4.md) 映像。映像也可驻留在块设备上。（例如磁盘、USB 闪存盘、DVD-ROM 等）。相应的设备节点将以 `.uzip` 后缀出现。 ```sh # gpart show da0 => 0 7833600 da0 BSD (3.7G) 0 2097152 1 freebsd-ufs (1.0G) 2097152 5736448 - free - (2.7G) # gpart add -t freebsd-ufs -s 1G da0 da0b added # dd if=/tmp/20160217_dcomp_zcomp.uzip bs=256k of=/dev/da0b 3190+1 records in 3190+1 records out 836331008 bytes transferred in 111.021489 secs (7533055 bytes/sec) # fsck -t ffs /dev/da0b.uzip ** /dev/da0b.uzip (NO WRITE) ** Last Mounted on /mnt ** Phase 1 - Check Blocks and Sizes ** Phase 2 - Check Pathnames ** Phase 3 - Check Connectivity ** Phase 4 - Check Reference Counts ** Phase 5 - Check Cyl groups 97455 files, 604242 used, 184741 free (2349 frags, 22799 blocks, 0.3% fragmentation) # mount -o ro /dev/da0b.uzip /mnt # df /dev/da0b.uzip Filesystem 1K-blocks Used Avail Capacity Mounted on /dev/da0b.uzip 3155932 2416968 738964 77% /mnt ``` `geom_uzip` 设备随后由 FreeBSD 内核用于访问解压后的数据。`geom_uzip` 驱动程序不允许对底层磁盘映像进行写操作。要检查哪些“providers”与给定 `geom_uzip` 设备匹配： ```sh # geom uzip list Geom name: md1.uzip Providers: 1. Name: md1.uzip Mediasize: 22003712 (21M) Sectorsize: 512 Consumers: 1. Name: md1 Mediasize: 9563648 (9.1M) Sectorsize: 512 Geom name: da0b.uzip Providers: 1. Name: da0b.uzip Mediasize: 3355443200 (3.1G) Sectorsize: 512 Consumers: 1. Name: da0b Mediasize: 1073741824 (1.0G) Sectorsize: 512 ``` `geom_uzip` 允许通过设置 `vfs.root.mountfrom` 可调参数从压缩磁盘分区挂载根文件系统。详见 loader.conf(5)。 ## 诊断 通过以下 sysctl 提供若干标志，用于跟踪 `geom_uzip` I/O 操作和 TOC 解析。 **`kern.geom.uzip.debug`** 日志级别。零禁用日志记录。较高的值为 `geom_uzip` 启用更详细的调试日志记录。支持的级别从 0（无日志记录）到 4（最大日志记录量）。 **`kern.geom.uzip.debug_block`** 记录涉及压缩簇号的操作。 ## 参见 GEOM(4), [md(4)](/man/man4/md.4.md), geom(8), mkuzip(8) ## 历史 Zstd 支持在 FreeBSD 13.0 中添加。 ## 作者 `geom_uzip` 驱动程序由 Max Khon 编写。块去重代码以及一些 `geom_uzip` 驱动程序优化由 Maxim Sobolev 贡献。LZMA 解压缩支持和 CLOOP 3.0 支持由 Aleksandr Rybalko 添加。 本手册页由 Ceri Davies 编写。 --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://book.bsdcn.org/man/man4/geom_uzip.4.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.