From a3cb877c54720615594eae08f6256a2f9f8e42ac Mon Sep 17 00:00:00 2001 From: Mikhail Zaslonko Date: Mon, 16 Oct 2023 22:14:59 +0200 Subject: [PATCH] README: Add info about bundled zlib MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Update Dependencies section for zipl with the information of zlib compression support for CCW-type standalone dump. Fixes: https://github.com/ibm-s390-linux/s390-tools/issues/157 Signed-off-by: Mikhail Zaslonko Reviewed-by: Jan Höppner Signed-off-by: Jan Höppner --- README.md | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/README.md b/README.md index efab471b..252fc0ba 100644 --- a/README.md +++ b/README.md @@ -386,6 +386,24 @@ the different tools are provided: - Packages: blktrace, multipath-tools, sg3-utils - Tools: rsync, tar, lsscsi +* zipl + For CCW-type DASD dump, zlib compression can be used to compress the dump + data before writing it to the DASD partition. It can benefit from + s390 on-chip compression accelerator (DFLTCC) and provide a faster dumping + process, hence lower system downtime. + The zlib version integrated with zipl (zipl/boot/zlib) is based on the Linux + kernel zlib (kernel version 6.3) which represents zlib version 1.1.3 with a + limited number of functions and a number of updates on top including s390 + hardware compression (DFLTCC) support. Also, all memory allocations are + performed in advance, which aligns with zipl requirements. + The CCW-type standalone dumper is built as a single binary and must be + loaded to stage2 during boot. Hence, all required zlib functions must be + integrated into it, and its size is restricted. To limit the size, only + deflate-related parts are integrated (no decompression is required during + dumping). + Removing the inflate modules and function prototypes are the only major + modifications made to the kernel version of zlib. + * zgetdump For building zgetdump you need OpenSSL version 1.1.0 or newer installed (openssl-devel.rpm). Also required is glib2