From 9e409f01201ec8621cdbb7a1b935e36f715d77d1 Mon Sep 17 00:00:00 2001 From: Daniel Sato Date: Thu, 9 Oct 2025 16:35:15 -0300 Subject: [PATCH] Adicionar Como adicionar Special Dev a zpool --- Como-adicionar-Special-Dev-a-zpool.md | 32 +++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100644 Como-adicionar-Special-Dev-a-zpool.md diff --git a/Como-adicionar-Special-Dev-a-zpool.md b/Como-adicionar-Special-Dev-a-zpool.md new file mode 100644 index 0000000..f73d950 --- /dev/null +++ b/Como-adicionar-Special-Dev-a-zpool.md @@ -0,0 +1,32 @@ +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 1M. 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 /` \ No newline at end of file