Differences

This shows you the differences between two versions of the page.

--- linux:fs:zfs:tuning:hdd [2026/07/07 13:48] – niziak
+++ linux:fs:zfs:tuning:hdd [2026/07/07 19:44] (current) – niziak
@@ Line 2: / Line 2: @@
 [[https://github.com/openzfs/zfs/discussions/14916|ZFS Send & RaidZ - Poor performance on HDD #14916]]
+All ''zfs_vdev'' read/write parameters are for number of parallel requests to one vdev (i.e. for 2x HDD mirror it is for each HDD).
+So for very slow 2xHDD mirror it is good to limit reads to 2 (2xHDD = 4 parallel reads), and write to 2.
 <code bash>
@@ Line 39: / Line 42: @@
 </code>
-Use of''bfq'' is mandatory. See [[#my_findings|my findings]].
+<code bash>
+# zfs list
+rpool/data/vm-101-disk-0                       37.5G   854G  37.5G  -
+rpool/data/vm-101-disk-0-backup                41.9G   854G  41.9G  -
+</code>
+====== bfq ======
+Use of''bfq'' is mandatory. See [[iosched#my_findings|my findings]].
 ====== prefetch ======