Adjusting ZFS resilvering speed

There are two kernel parameters that can be adjusted if ZFS resilvering speed is too slow/fast:

zfs_resilver_delay /* number of ticks to delay resilver */


zfs_resilver_min_time_ms /* min millisecs to resilver per txg */

In some cases the values can be too low or two high (e.g. when using Mirroring vs. RAIDZ).

A boost could be:

# echo zfs_resilver_delay/W0|mdb -kw
# echo zfs_resilver_min_time_ms/W0t3000|mdb -kw

whereas a handbrake is e.g.:

# echo zfs_resilver_delay/W2|mdb -kw
# echo zfs_resilver_min_time_ms/W0t300|mdb -kw

Disclaimer: Use at your own risk. Do not try on production systems without contacting support first.


Anonymous said…
Hi Mika,

Is there any way to contact you, I cannot see any emails or other contact information anywhere.

t: Jukka
Mika said…
You can email me through

Popular posts from this blog

Heating up the Data Pipeline (Part 1)

Opensolaris, Huawei E220, Swisscom and Sunrise