errors: No known data errors
----
-The `zfs` command is used configure and manage your ZFS file
-systems. The following command lists all file systems after
-installation:
+The `zfs` command is used to configure and manage your ZFS file systems. The
+following command lists all file systems after installation:
----
# zfs list
There are a few factors to take into consideration when choosing the layout of
a ZFS pool. The basic building block of a ZFS pool is the virtual device, or
`vdev`. All vdevs in a pool are used equally and the data is striped among them
-(RAID0). Check the `zpool(8)` manpage for more details on vdevs.
+(RAID0). Check the `zpoolconcepts(7)` manpage for more details on vdevs.
[[sysadmin_zfs_raid_performance]]
Performance
in regard to IOPS with a lot of bandwidth. How much bandwidth depends on the
size of the RAIDZ vdev and the redundancy level.
+A 'dRAID' pool should match the performance of an equivalent 'RAIDZ' pool.
+
For running VMs, IOPS is the more important metric in most situations.
.Changing a failed bootable device
-Depending on how {pve} was installed it is either using `systemd-boot` or `grub`
-through `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
+Depending on how {pve} was installed it is either using `systemd-boot` or GRUB
+through `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:
----
bootable disks setup by the {pve} installer since version 5.4. For details, see
xref:sysboot_proxmox_boot_setup[Setting up a new partition for use as synced ESP].
-NOTE: make sure to pass 'grub' as mode to `proxmox-boot-tool init` if
-`proxmox-boot-tool status` indicates your current disks are using Grub,
+NOTE: Make sure to pass 'grub' as mode to `proxmox-boot-tool init` if
+`proxmox-boot-tool status` indicates your current disks are using GRUB,
especially if Secure Boot is enabled!
-.With plain `grub`:
+.With plain GRUB:
----
# grub-install <new disk>
----
-NOTE: plain `grub` is only used on systems installed with {pve} 6.3 or earlier,
+NOTE: Plain GRUB is only used on systems installed with {pve} 6.3 or earlier,
which have not been manually migrated to using `proxmox-boot-tool` yet.
~~~~~~~~~~~~~~~~~~~~~~
ZFS uses '50 %' of the host memory for the **A**daptive **R**eplacement
-**C**ache (ARC) by default. Allocating enough memory for the ARC is crucial for
-IO performance, so reduce it with caution. As a general rule of thumb, allocate
-at least +2 GiB Base + 1 GiB/TiB-Storage+. For example, if you have a pool with
-+8 TiB+ of available storage space then you should use +10 GiB+ of memory for
-the ARC.
+**C**ache (ARC) by default. For new installations starting with {pve} 8.1, the
+ARC usage limit will be set to '10 %' of the installed physical memory, clamped
+to a maximum of +16 GiB+. This value is written to `/etc/modprobe.d/zfs.conf`.
+
+Allocating enough memory for the ARC is crucial for IO performance, so reduce it
+with caution. As a general rule of thumb, allocate at least +2 GiB Base + 1
+GiB/TiB-Storage+. For example, if you have a pool with +8 TiB+ of available
+storage space then you should use +10 GiB+ of memory for the ARC.
+
+ZFS also enforces a minimum value of +64 MiB+.
You can change the ARC usage limit for the current boot (a reboot resets this
change again) by writing to the +zfs_arc_max+ module parameter directly:
echo "$[10 * 1024*1024*1024]" >/sys/module/zfs/parameters/zfs_arc_max
----
-To *permanently change* the ARC limits, add the following line to
-`/etc/modprobe.d/zfs.conf`:
+To *permanently change* the ARC limits, add (or change if already present) the
+following line to `/etc/modprobe.d/zfs.conf`:
--------
options zfs zfs_arc_max=8589934592
----
WARNING: There is currently no support for booting from pools with encrypted
-datasets using Grub, and only limited support for automatically unlocking
+datasets using GRUB, and only limited support for automatically unlocking
encrypted datasets on boot. Older versions of ZFS without encryption support
will not be able to decrypt stored data.
In fact, there are some downsides to enabling new features:
-* A system with root on ZFS, that still boots using `grub` will become
+* 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.
+ 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
+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]).
projects / pve-docs.git / blobdiff