Re: high load, no bottleneck

[David Holland <dholland-tech%netbsd.org@localhost>]

On Wed, Sep 18, 2013 at 03:34:19AM +0200, Emmanuel Dreyfus wrote:
 > Christos Zoulas <christos%zoulas.com@localhost> wrote:
 > 
 > > On large filesystems with many files fsck can take a really long time after
 > > a crash. In my personal experience power outages are much less frequent 
 > > than
 > > crashes (I crash quite a lot since I always fiddle with things). If you
 > > don't care about fsck time, you don't need WAPBL. 
 > 
 > But you just told me that I will need a fsck after crash now I am
 > running with vfs.wapbl.flush_disk_cache=0 so I wonder if I should not
 > just mount without -o log. What are WAPBL benefits when running with
 > vfs.wapbl.flush_disk_cache=0?

To the extent it's correct (which may vary) it's much faster.

The downside is that without the cache flushing there's some chance
that fsck won't be able to repair things afterwards.

The only real solution is to figure out why it's being slow.

(as far as I know wapbl doesn't support an external journal, and even
if it did putting one on an SSD that doesn't have power failure
recovery is worse than useless)

-- 
David A. Holland
dholland%netbsd.org@localhost