I moved the section on creating swap partitions on ZFS between the "Disk Health Monitoring" section and the "Logical Volume Manager" section. I also incorporated all suggestions Fiona made, except one: No comma was put before "because" because the subordinate clause is introduced by "because". One only puts commas after suboridnate clauses if these introduce a sentence.
Signed-off-by: Alexander Abraham <a.abra...@proxmox.com> --- local-zfs.adoc | 42 +--------------------------------------- pve-swap-on-zfs.adoc | 46 ++++++++++++++++++++++++++++++++++++++++++++ sysadmin.adoc | 2 ++ 3 files changed, 49 insertions(+), 41 deletions(-) create mode 100644 pve-swap-on-zfs.adoc diff --git a/local-zfs.adoc b/local-zfs.adoc index c64fb27..3c9564f 100644 --- a/local-zfs.adoc +++ b/local-zfs.adoc @@ -1,6 +1,7 @@ [[chapter_zfs]] ZFS on Linux ------------ + ifdef::wiki[] :pve-toplevel: endif::wiki[] @@ -622,47 +623,6 @@ time this value changes: You *must reboot* to activate these changes. ==== - -[[zfs_swap]] -SWAP on ZFS -~~~~~~~~~~~ - -Swap-space created on a zvol may generate some troubles, like blocking the -server or generating a high IO load, often seen when starting a Backup -to an external Storage. - -We strongly recommend to use enough memory, so that you normally do not -run into low memory situations. Should you need or want to add swap, it is -preferred to create a partition on a physical disk and use it as a swap device. -You can leave some space free for this purpose in the advanced options of the -installer. Additionally, you can lower the -``swappiness'' value. A good value for servers is 10: - ----- -# sysctl -w vm.swappiness=10 ----- - -To make the swappiness persistent, open `/etc/sysctl.conf` with -an editor of your choice and add the following line: - --------- -vm.swappiness = 10 --------- - -.Linux kernel `swappiness` parameter values -[width="100%",cols="<m,2d",options="header"] -|=========================================================== -| Value | Strategy -| vm.swappiness = 0 | The kernel will swap only to avoid -an 'out of memory' condition -| vm.swappiness = 1 | Minimum amount of swapping without -disabling it entirely. -| vm.swappiness = 10 | This value is sometimes recommended to -improve performance when sufficient memory exists in a system. -| vm.swappiness = 60 | The default value. -| vm.swappiness = 100 | The kernel will swap aggressively. -|=========================================================== - [[zfs_encryption]] Encrypted ZFS Datasets ~~~~~~~~~~~~~~~~~~~~~~ diff --git a/pve-swap-on-zfs.adoc b/pve-swap-on-zfs.adoc new file mode 100644 index 0000000..aec3a70 --- /dev/null +++ b/pve-swap-on-zfs.adoc @@ -0,0 +1,46 @@ +[[zfs_swap]] +SWAP on ZFS +----------- + +It is strongly recommended to not use a ZFS volume for creating a swap +partition because this could lead to deadlocks. These deadlocks could +cause the affected system to freeze. The OpenZFS documentation +footnote:[https://openzfs.github.io/openzfs-docs/Project%20and%20Community/FAQ.html#using-a-zvol-for-a-swap-device-on-linux] +warns about using a ZFS volume for creating a swap partition. + +[[creating_swap_partitions]] +Creating SWAP Partitions +------------------------ + +We strongly recommend to use enough memory, so that you normally do not +run into low memory situations. Should you need or want to add swap, it is +preferred to create a partition on a physical disk and use it as a swap device. +You can leave some space free for this purpose in the advanced options of the +installer. Additionally, you can lower the +``swappiness'' value. A good value for servers is 10: + +---- +# sysctl -w vm.swappiness=10 +---- + +To make the swappiness persistent, open `/etc/sysctl.conf` with +an editor of your choice and add the following line: + +-------- +vm.swappiness = 10 +-------- + +.Linux kernel `swappiness` parameter values +[width="100%",cols="<m,2d",options="header"] +|=========================================================== +| Value | Strategy +| vm.swappiness = 0 | The kernel will swap only to avoid +an 'out of memory' condition +| vm.swappiness = 1 | Minimum amount of swapping without +disabling it entirely. +| vm.swappiness = 10 | This value is sometimes recommended to +improve performance when sufficient memory exists in a system. +| vm.swappiness = 60 | The default value. +| vm.swappiness = 100 | The kernel will swap aggressively. +|=========================================================== + diff --git a/sysadmin.adoc b/sysadmin.adoc index dd43f73..9b2db52 100644 --- a/sysadmin.adoc +++ b/sysadmin.adoc @@ -71,6 +71,8 @@ include::pve-external-metric-server.adoc[] include::pve-disk-health-monitoring.adoc[] +include::pve-swap-on-zfs.adoc[] + include::local-lvm.adoc[] include::local-zfs.adoc[] -- 2.39.5 _______________________________________________ pve-devel mailing list pve-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel
