CD9660/md(4)/UFS22 silly behaviour
yanegomi at gmail.com
Sun Jan 8 23:43:20 UTC 2012
On Sun, Jan 8, 2012 at 3:01 PM, Freddie Cash <fjwcash at gmail.com> wrote:
> On Sun, Jan 8, 2012 at 2:33 PM, Kostik Belousov <kostikbel at gmail.com> wrote:
>> On Sun, Jan 08, 2012 at 10:31:06PM +0000, Poul-Henning Kamp wrote:
>>> In message <20120108222720.GN31224 at deviant.kiev.zoral.com.ua>, Kostik Belousov
>>> >What is the access patern ? Is it random access, or sequential read
>>> >(from the cd9660 POV) ?
>>> Random access to files in the CD9660 filesystem, which stores files
>>> in sequential 2K blocks.
>> Then it is reasonable. UFS reads full blocks. If you want/plan to use
>> UFS volume for small reads exclusively, you can newfs it with much
>> smaller block size, e.g. 8KB or even 4KB.
> I think the complaint is that UFS is reading 32 KB (which includes the
> 2 KB block and 15 others that will be needed right after) but not
> caching the 30 KB of data that follows the requested 2 KB.
Speaking of the increase in block size and frag size, on the
FreeNAS side of the house we discovered that the new values make sense
with larger disks and memory disks, but they don't make sense with
rc.initdiskless's generated md's, et all. So we've hacked
rc.initdiskless to use smaller sizes.
Just a thought since we're talking about this change from the 8.x
defaults to the 9.x defaults.
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