From 1a4718c9c13b396632c84496d89d1faee244f260 Mon Sep 17 00:00:00 2001 From: George Melikov Date: Sun, 30 Oct 2022 21:06:54 +0300 Subject: [PATCH] Update Workload Tuning.rst Add info about init_on_alloc --- .../Workload Tuning.rst | 28 +++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/docs/Performance and Tuning/Workload Tuning.rst b/docs/Performance and Tuning/Workload Tuning.rst index 754ce59..2f2c85d 100644 --- a/docs/Performance and Tuning/Workload Tuning.rst +++ b/docs/Performance and Tuning/Workload Tuning.rst @@ -342,6 +342,33 @@ the whole_disk field set to true, such that a pool imported on another platform that was created on FreeBSD will always be treated as the whole disks were given to ZFS. +.. _OS_specific: + +OS/distro-specific recommendations +---------------------------------- + +.. _linux_specific: + +Linux +~~~~~ + +init_on_alloc +^^^^^^^^^^^^^ +Some Linux distributions (at least Debian, Ubuntu) enable +``init_on_alloc`` option as security precaution by default. +This option can help to [#init_on_alloc]_: + + prevent possible information leaks and + make control-flow bugs that depend on uninitialized values more + deterministic. + +Unfortunately, it can lower ARC throughput considerably +(see `bug `__). + +If you're ready to cope with these security risks [#init_on_alloc]_, +you may disable it +by setting ``init_on_alloc=0`` in the GRUB kernel boot parameters. + .. _general_recommendations: General recommendations @@ -716,3 +743,4 @@ AIO should be used to maximize IOPS when using files for guest storage. .. [#sqlite_ps] .. [#sqlite_ps_change] .. [#FS_CASEFOLD_FL] +.. [#init_on_alloc]