~~~~~~~~
ZFS depends heavily on memory, so you need at least 8GB to start. In
-practice, use as much you can get for your hardware/budget. To prevent
+practice, use as much as you can get for your hardware/budget. To prevent
data corruption, we recommend the use of high quality ECC RAM.
If you use a dedicated cache and/or log disk, you should use an
enterprise class SSD (e.g. Intel SSD DC S3700 Series). This can
increase the overall performance significantly.
-IMPORTANT: Do not use ZFS on top of hardware controller which has its
-own cache management. ZFS needs to directly communicate with disks. An
-HBA adapter is the way to go, or something like LSI controller flashed
-in ``IT'' mode.
+IMPORTANT: Do not use ZFS on top of a hardware RAID controller which has its
+own cache management. ZFS needs to communicate directly with the disks. An
+HBA adapter or something like an LSI controller flashed in ``IT'' mode is more
+appropriate.
If you are experimenting with an installation of {pve} inside a VM
(Nested Virtualization), don't use `virtio` for disks of that VM,
-since they are not supported by ZFS. Use IDE or SCSI instead (works
-also with `virtio` SCSI controller type).
+as they are not supported by ZFS. Use IDE or SCSI instead (also works
+with the `virtio` SCSI controller type).
Installation as Root File System
Bootloader
~~~~~~~~~~
-Depending on whether the system is booted in EFI or legacy BIOS mode the
-{pve} installer sets up either `grub` or `systemd-boot` as main bootloader.
-See the chapter on xref:sysboot[{pve} host bootladers] for details.
+{pve} uses xref:sysboot_proxmox_boot_tool[`proxmox-boot-tool`] to manage the
+bootloader configuration.
+See the chapter on xref:sysboot[{pve} host bootloaders] for details.
ZFS Administration
.Changing a failed bootable device
-Depending on how {pve} was installed it is either using `grub` or `systemd-boot`
-as bootloader (see xref:sysboot[Host Bootloader]).
+Depending on how {pve} was installed it is either using `proxmox-boot-tool`
+footnote:[Systems installed with {pve} 6.4 or later, EFI systems installed with
+{pve} 5.4 or later] or plain `grub` as bootloader (see
+xref:sysboot[Host Bootloader]). You can check by running:
+
+----
+# proxmox-boot-tool status
+----
The first steps of copying the partition table, reissuing GUIDs and replacing
the ZFS partition are the same. To make the system bootable from the new disk,
NOTE: Use the `zpool status -v` command to monitor how far the resilvering
process of the new disk has progressed.
-.With `systemd-boot`:
+.With `proxmox-boot-tool`:
----
-# pve-efiboot-tool format <new disk's ESP>
-# pve-efiboot-tool init <new disk's ESP>
+# proxmox-boot-tool format <new disk's ESP>
+# proxmox-boot-tool init <new disk's ESP>
----
NOTE: `ESP` stands for EFI System Partition, which is setup as partition #2 on
bootable disks setup by the {pve} installer since version 5.4. For details, see
-xref:sysboot_systemd_boot_setup[Setting up a new partition for use as synced ESP].
+xref:sysboot_proxmox_boot_setup[Setting up a new partition for use as synced ESP].
.With `grub`:
----
To activate the daemon it is necessary to edit `/etc/zfs/zed.d/zed.rc` with your
-favourite editor, and uncomment the `ZED_EMAIL_ADDR` setting:
+favorite editor, and uncomment the `ZED_EMAIL_ADDR` setting:
--------
ZED_EMAIL_ADDR="root"
This example setting limits the usage to 8 GiB ('8 * 2^30^').
+IMPORTANT: In case your desired +zfs_arc_max+ value is lower than or equal to
++zfs_arc_min+ (which defaults to 1/32 of the system memory), +zfs_arc_max+ will
+be ignored unless you also set +zfs_arc_min+ to at most +zfs_arc_max - 1+.
+
+----
+echo "$[8 * 1024*1024*1024 - 1]" >/sys/module/zfs/parameters/zfs_arc_min
+echo "$[8 * 1024*1024*1024]" >/sys/module/zfs/parameters/zfs_arc_max
+----
+
+This example setting (temporarily) limits the usage to 8 GiB ('8 * 2^30^') on
+systems with more than 256 GiB of total memory, where simply setting
++zfs_arc_max+ alone would not work.
+
[IMPORTANT]
====
If your root file system is ZFS, you must update your initramfs every
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 swapdevice.
+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:
----
# zfs set special_small_blocks=0 <pool>/<filesystem>
----
+
+[[sysadmin_zfs_features]]
+ZFS Pool Features
+~~~~~~~~~~~~~~~~~
+
+Changes to the on-disk format in ZFS are only made between major version changes
+and are specified through *features*. All features, as well as the general
+mechanism are well documented in the `zpool-features(5)` manpage.
+
+Since enabling new features can render a pool not importable by an older version
+of ZFS, this needs to be done actively by the administrator, by running
+`zpool upgrade` on the pool (see the `zpool-upgrade(8)` manpage).
+
+Unless you need to use one of the new features, there is no upside to enabling
+them.
+
+In fact, there are some downsides to enabling new features:
+
+* A system with root on ZFS, that still boots using `grub` will become
+ unbootable if a new feature is active on the rpool, due to the incompatible
+ implementation of ZFS in grub.
+* The system will not be able to import any upgraded pool when booted with an
+ older kernel, which still ships with the old ZFS modules.
+* Booting an older {pve} ISO to repair a non-booting system will likewise not
+ work.
+
+IMPORTANT: Do *not* upgrade your rpool if your system is still booted with
+`grub`, as this will render your system unbootable. This includes systems
+installed before {pve} 5.4, and systems booting with legacy BIOS boot (see
+xref:sysboot_determine_bootloader_used[how to determine the bootloader]).
+
+.Enable new features for a ZFS pool:
+----
+# zpool upgrade <pool>
+----
projects / pve-docs.git / blobdiff