docs: move host sysadmin out to own chapter, fix ZFS one

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
This commit is contained in:
Thomas Lamprecht 2020-07-08 18:15:33 +02:00
parent 1f24d9114c
commit 24406ebc0c
5 changed files with 64 additions and 43 deletions

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@ -1,9 +1,8 @@
Administration Guide
====================
Backup Management
=================
The administration guide.
.. todo:: either add a bit more explanation or remove the previous sentence
.. The administration guide.
.. todo:: either add a bit more explanation or remove the previous sentence
Terminology
-----------
@ -182,6 +181,7 @@ File Layout
After creating a datastore, the following default layout will appear:
.. code-block:: console
# ls -arilh /backup/disk1/store1
276493 -rw-r--r-- 1 backup backup 0 Jul 8 12:35 .lock
276490 drwxr-x--- 1 backup backup 1064960 Jul 8 12:35 .chunks
@ -192,6 +192,7 @@ The `.chunks` directory contains folders, starting from `0000` and taking hexade
directories will store the chunked data after a backup operation has been executed.
.. code-block:: console
# ls -arilh /backup/disk1/store1/.chunks
545824 drwxr-x--- 2 backup backup 4.0K Jul 8 12:35 ffff
545823 drwxr-x--- 2 backup backup 4.0K Jul 8 12:35 fffe
@ -933,7 +934,3 @@ After that you should be able to see storage status with:
.. include:: command-line-tools.rst
.. include:: services.rst
.. include host system admin at the end
.. include:: sysadmin.rst

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@ -112,7 +112,7 @@ exclude_patterns = [
'pxar/man1.rst',
'epilog.rst',
'pbs-copyright.rst',
'sysadmin.rst',
'local-zfs.rst'
'package-repositories.rst',
]

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@ -19,6 +19,7 @@ in the section entitled "GNU Free Documentation License".
introduction.rst
installation.rst
administration-guide.rst
sysadmin.rst
.. raw:: latex

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@ -1,6 +1,5 @@
ZFS on Linux
=============
.. code-block:: console.. code-block:: console.. code-block:: console
------------
ZFS is a combined file system and logical volume manager designed by
Sun Microsystems. There is no need for manually compile ZFS modules - all
@ -31,7 +30,7 @@ General ZFS advantages
* Encryption
Hardware
---------
~~~~~~~~~
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
@ -47,10 +46,8 @@ HBA adapter is the way to go, or something like LSI controller flashed
in ``IT`` mode.
ZFS Administration
------------------
~~~~~~~~~~~~~~~~~~
This section gives you some usage examples for common tasks. ZFS
itself is really powerful and provides many options. The main commands
@ -58,61 +55,68 @@ to manage ZFS are `zfs` and `zpool`. Both commands come with great
manual pages, which can be read with:
.. code-block:: console
# man zpool
# man zfs
Create a new zpool
~~~~~~~~~~~~~~~~~~
^^^^^^^^^^^^^^^^^^
To create a new pool, at least one disk is needed. The `ashift` should
have the same sector-size (2 power of `ashift`) or larger as the
underlying disk.
.. code-block:: console
# zpool create -f -o ashift=12 <pool> <device>
Create a new pool with RAID-0
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Minimum 1 disk
.. code-block:: console
# zpool create -f -o ashift=12 <pool> <device1> <device2>
Create a new pool with RAID-1
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Minimum 2 disks
.. code-block:: console
# zpool create -f -o ashift=12 <pool> mirror <device1> <device2>
Create a new pool with RAID-10
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Minimum 4 disks
.. code-block:: console
# zpool create -f -o ashift=12 <pool> mirror <device1> <device2> mirror <device3> <device4>
Create a new pool with RAIDZ-1
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Minimum 3 disks
.. code-block:: console
# zpool create -f -o ashift=12 <pool> raidz1 <device1> <device2> <device3>
Create a new pool with RAIDZ-2
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Minimum 4 disks
.. code-block:: console
# zpool create -f -o ashift=12 <pool> raidz2 <device1> <device2> <device3> <device4>
Create a new pool with cache (L2ARC)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
It is possible to use a dedicated cache drive partition to increase
the performance (use SSD).
@ -121,10 +125,11 @@ As `<device>` it is possible to use more devices, like it's shown in
"Create a new pool with RAID*".
.. code-block:: console
# zpool create -f -o ashift=12 <pool> <device> cache <cache_device>
Create a new pool with log (ZIL)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
It is possible to use a dedicated cache drive partition to increase
the performance (SSD).
@ -133,10 +138,11 @@ As `<device>` it is possible to use more devices, like it's shown in
"Create a new pool with RAID*".
.. code-block:: console
# zpool create -f -o ashift=12 <pool> <device> log <log_device>
Add cache and log to an existing pool
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
If you have a pool without cache and log. First partition the SSD in
2 partition with `parted` or `gdisk`
@ -148,18 +154,20 @@ physical memory, so this is usually quite small. The rest of the SSD
can be used as cache.
.. code-block:: console
# zpool add -f <pool> log <device-part1> cache <device-part2>
Changing a failed device
~~~~~~~~~~~~~~~~~~~~~~~~
^^^^^^^^^^^^^^^^^^^^^^^^
.. code-block:: console
# zpool replace -f <pool> <old device> <new device>
Changing a failed bootable device
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Depending on how Proxmox Backup was installed it is either using `grub` or `systemd-boot`
as bootloader.
@ -169,6 +177,7 @@ the ZFS partition are the same. To make the system bootable from the new disk,
different steps are needed which depend on the bootloader in use.
.. code-block:: console
# sgdisk <healthy bootable device> -R <new device>
# sgdisk -G <new device>
# zpool replace -f <pool> <old zfs partition> <new zfs partition>
@ -178,6 +187,7 @@ different steps are needed which depend on the bootloader in use.
With `systemd-boot`:
.. code-block:: console
# pve-efiboot-tool format <new disk's ESP>
# pve-efiboot-tool init <new disk's ESP>
@ -190,12 +200,13 @@ With `grub`:
Usually `grub.cfg` is located in `/boot/grub/grub.cfg`
.. code-block:: console
# grub-install <new disk>
# grub-mkconfig -o /path/to/grub.cfg
Activate E-Mail Notification
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ZFS comes with an event daemon, which monitors events generated by the
ZFS kernel module. The daemon can also send emails on ZFS events like
@ -203,12 +214,14 @@ pool errors. Newer ZFS packages ship the daemon in a separate package,
and you can install it using `apt-get`:
.. code-block:: console
# apt-get install zfs-zed
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:
.. code-block:: console
ZED_EMAIL_ADDR="root"
Please note Proxmox Backup forwards mails to `root` to the email address
@ -218,7 +231,7 @@ IMPORTANT: The only setting that is required is `ZED_EMAIL_ADDR`. All
other settings are optional.
Limit ZFS Memory Usage
~~~~~~~~~~~~~~~~~~~~~~
^^^^^^^^^^^^^^^^^^^^^^
It is good to use at most 50 percent (which is the default) of the
system memory for ZFS ARC to prevent performance shortage of the
@ -226,6 +239,7 @@ host. Use your preferred editor to change the configuration in
`/etc/modprobe.d/zfs.conf` and insert:
.. code-block:: console
options zfs zfs_arc_max=8589934592
This example setting limits the usage to 8GB.
@ -233,11 +247,12 @@ This example setting limits the usage to 8GB.
.. IMPORTANT:: If your root file system is ZFS you must update your initramfs every time this value changes:
.. code-block:: console
# update-initramfs -u
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
@ -251,31 +266,35 @@ installer. Additionally, you can lower the `swappiness` value.
A good value for servers is 10:
.. code-block:: console
# 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:
.. code-block:: console
vm.swappiness = 10
.. table:: Linux kernel `swappiness` parameter values
:widths:auto
========= ============
==================== ===============================================================
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 = 10 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 Compression
~~~~~~~~~~~~~~~
^^^^^^^^^^^^^^^
To activate compression:
.. code-block:: console
# zpool set compression=lz4 <pool>
We recommend using the `lz4` algorithm, since it adds very little CPU overhead.
@ -286,12 +305,13 @@ I/O performance.
You can disable compression at any time with:
.. code-block:: console
# zfs set compression=off <dataset>
Only new blocks will be affected by this change.
ZFS Special Device
~~~~~~~~~~~~~~~~~~
^^^^^^^^^^^^^^^^^^
Since version 0.8.0 ZFS supports `special` devices. A `special` device in a
pool is used to store metadata, deduplication tables, and optionally small
@ -312,11 +332,13 @@ performance. Use fast SSDs for the `special` device.
Create a pool with `special` device and RAID-1:
.. code-block:: console
# zpool create -f -o ashift=12 <pool> mirror <device1> <device2> special mirror <device3> <device4>
Adding a `special` device to an existing pool with RAID-1:
.. code-block:: console
# zpool add <pool> special mirror <device1> <device2>
ZFS datasets expose the `special_small_blocks=<size>` property. `size` can be
@ -335,20 +357,23 @@ in the pool will opt in for small file blocks).
Opt in for all file smaller than 4K-blocks pool-wide:
.. code-block:: console
# zfs set special_small_blocks=4K <pool>
Opt in for small file blocks for a single dataset:
.. code-block:: console
# zfs set special_small_blocks=4K <pool>/<filesystem>
Opt out from small file blocks for a single dataset:
.. code-block:: console
# zfs set special_small_blocks=0 <pool>/<filesystem>
Troubleshooting
~~~~~~~~~~~~~~~
^^^^^^^^^^^^^^^
Corrupted cachefile
@ -358,11 +383,13 @@ boot until mounted manually later.
For each pool, run:
.. code-block:: console
# zpool set cachefile=/etc/zfs/zpool.cache POOLNAME
and afterwards update the `initramfs` by running:
.. code-block:: console
# update-initramfs -u -k all
and finally reboot your node.

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@ -1,5 +1,5 @@
Host System Administration
--------------------------
==========================
`Proxmox Backup`_ is based on the famous Debian_ Linux
distribution. That means that you have access to the whole world of
@ -23,8 +23,4 @@ either explain things which are different on `Proxmox Backup`_, or
tasks which are commonly used on `Proxmox Backup`_. For other topics,
please refer to the standard Debian documentation.
ZFS
~~~
.. todo:: Add local ZFS admin guide (local.zfs.adoc)
.. include:: local-zfs.rst