X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=local-zfs.adoc;h=5cce6778bd81dafa800e456a9bb1e8613c78a338;hb=3d5c55fca7d31860c7453b0dc2eabc56762b3462;hp=b4fb7dbf1e8ffdb1a83ca595107130c001ba0e5a;hpb=5dfeeece548c9304fc6cbd51b17679bafeff2bee;p=pve-docs.git diff --git a/local-zfs.adoc b/local-zfs.adoc index b4fb7db..5cce677 100644 --- a/local-zfs.adoc +++ b/local-zfs.adoc @@ -178,41 +178,55 @@ 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. - zpool create -f -o ashift=12 +---- +# zpool create -f -o ashift=12 +---- -To activate compression +To activate compression (see section <>): - zfs set compression=lz4 +---- +# zfs set compression=lz4 +---- .Create a new pool with RAID-0 -Minimum 1 Disk +Minimum 1 disk - zpool create -f -o ashift=12 +---- +# zpool create -f -o ashift=12 +---- .Create a new pool with RAID-1 -Minimum 2 Disks +Minimum 2 disks - zpool create -f -o ashift=12 mirror +---- +# zpool create -f -o ashift=12 mirror +---- .Create a new pool with RAID-10 -Minimum 4 Disks +Minimum 4 disks - zpool create -f -o ashift=12 mirror mirror +---- +# zpool create -f -o ashift=12 mirror mirror +---- .Create a new pool with RAIDZ-1 -Minimum 3 Disks +Minimum 3 disks - zpool create -f -o ashift=12 raidz1 +---- +# zpool create -f -o ashift=12 raidz1 +---- .Create a new pool with RAIDZ-2 -Minimum 4 Disks +Minimum 4 disks - zpool create -f -o ashift=12 raidz2 +---- +# zpool create -f -o ashift=12 raidz2 +---- .Create a new pool with cache (L2ARC) @@ -222,7 +236,9 @@ the performance (use SSD). As `` it is possible to use more devices, like it's shown in "Create a new pool with RAID*". - zpool create -f -o ashift=12 cache +---- +# zpool create -f -o ashift=12 cache +---- .Create a new pool with log (ZIL) @@ -232,7 +248,9 @@ the performance(SSD). As `` it is possible to use more devices, like it's shown in "Create a new pool with RAID*". - zpool create -f -o ashift=12 log +---- +# zpool create -f -o ashift=12 log +---- .Add cache and log to an existing pool @@ -245,19 +263,25 @@ The maximum size of a log device should be about half the size of physical memory, so this is usually quite small. The rest of the SSD can be used as cache. - zpool add -f log cache +---- +# zpool add -f log cache +---- .Changing a failed device - zpool replace -f +---- +# zpool replace -f +---- .Changing a failed bootable device when using systemd-boot - sgdisk -R - sgdisk -G - zpool replace -f - pve-efiboot-tool format - pve-efiboot-tool init +---- +# sgdisk -R +# sgdisk -G +# zpool replace -f +# pve-efiboot-tool format +# pve-efiboot-tool init +---- 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 @@ -309,7 +333,9 @@ This example setting limits the usage to 8GB. If your root file system is ZFS you must update your initramfs every time this value changes: - update-initramfs -u +---- +# update-initramfs -u +---- ==== @@ -328,7 +354,9 @@ 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 +---- +# 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: @@ -431,3 +459,95 @@ See the `encryptionroot`, `encryption`, `keylocation`, `keyformat` and `keystatus` properties, the `zfs load-key`, `zfs unload-key` and `zfs change-key` commands and the `Encryption` section from `man zfs` for more details and advanced usage. + + +[[zfs_compression]] +Compression in ZFS +~~~~~~~~~~~~~~~~~~ + +When compression is enabled on a dataset, ZFS tries to compress all *new* +blocks before writing them and decompresses them on reading. Already +existing data will not be compressed retroactively. + +You can enable compression with: + +---- +# zfs set compression= +---- + +We recommend using the `lz4` algorithm, because it adds very little CPU +overhead. Other algorithms like `lzjb` and `gzip-N`, where `N` is an +integer from `1` (fastest) to `9` (best compression ratio), are also +available. Depending on the algorithm and how compressible the data is, +having compression enabled can even increase I/O performance. + +You can disable compression at any time with: + +---- +# zfs set compression=off +---- + +Again, 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 +file blocks. + +A `special` device can improve the speed of a pool consisting of slow spinning +hard disks with a lot of metadata changes. For example workloads that involve +creating, updating or deleting a large number of files will benefit from the +presence of a `special` device. ZFS datasets can also be configured to store +whole small files on the `special` device which can further improve the +performance. Use fast SSDs for the `special` device. + +IMPORTANT: The redundancy of the `special` device should match the one of the +pool, since the `special` device is a point of failure for the whole pool. + +WARNING: Adding a `special` device to a pool cannot be undone! + +.Create a pool with `special` device and RAID-1: + +---- +# zpool create -f -o ashift=12 mirror special mirror +---- + +.Add a `special` device to an existing pool with RAID-1: + +---- +# zpool add special mirror +---- + +ZFS datasets expose the `special_small_blocks=` property. `size` can be +`0` to disable storing small file blocks on the `special` device or a power of +two in the range between `512B` to `128K`. After setting the property new file +blocks smaller than `size` will be allocated on the `special` device. + +IMPORTANT: If the value for `special_small_blocks` is greater than or equal to +the `recordsize` (default `128K`) of the dataset, *all* data will be written to +the `special` device, so be careful! + +Setting the `special_small_blocks` property on a pool will change the default +value of that property for all child ZFS datasets (for example all containers +in the pool will opt in for small file blocks). + +.Opt in for all file smaller than 4K-blocks pool-wide: + +---- +# zfs set special_small_blocks=4K +---- + +.Opt in for small file blocks for a single dataset: + +---- +# zfs set special_small_blocks=4K / +---- + +.Opt out from small file blocks for a single dataset: + +---- +# zfs set special_small_blocks=0 / +----