Project

General

Profile

Actions

Bug #54

closed

metaslab_min_alloc_size may be too big

Added by Garrett D'Amore almost 12 years ago. Updated almost 11 years ago.

Status:
Closed
Priority:
Normal
Assignee:
-
Category:
-
Start date:
2010-08-18
Due date:
% Done:

0%

Estimated time:
Difficulty:
Medium
Tags:
needs-triage
Gerrit CR:

Description

See bugs.opensolaris.org: CR 6962304. It seems like we could adjust this tunable to be a bit more sane.

The current default value of metaslab_min_alloc_size is 10M

Several systems which have pools that are in the neighborhood of 70% or so full
were observed spending a lot of time in metaslab-related code and were generally seen as slow.

Someone suggested patching metaslab_min_alloc_size to 4K, and this has significantly reduced the amount of cpu used by zfs and made the systems significantly more responsive.

Looks like the default value is wrong.

Workaround:

Add the following to /etc/system and reboot:

  • Work around 6962304
    set zfs:metaslab_min_alloc_size=0x1000
Actions

Also available in: Atom PDF