FreeBSD and poor ata performance

[Kenneth Culver]

Quoting fandino <fandino at ng.fadesa.es>:

> Kenneth Culver wrote:
>>> well, my usage pattern is write a big file and few seconds later 
>>> read it. So my tests
>>> were valid for the use of the computer.
>>>
>>> But you have reason, I must provide a more formal report. I redid all test
>>> with bonnie++ and results shows Linux (56848 K/sec) two times faster than
>>> FreeBSD (26347 K/sec)
>>>
>>> Any help will be appreciated!
>>>
>>>
>>> Linux test  (slackware 8.1, kernel 2.4.18, ext2 filesystem):
>>
>>
>> This test isn't really a fair test either. The ext2 filesystem uses 
>> async io,
>> and doesn't do any kind of journaling to ensure data integrity in 
>> the event of
>> a crash. FreeBSD isn't using async, it uses softupdates. Because of this
>> FreeBSD SHOULD be slower... but it'll be a lot more reliable than 
>> linux in the
>> event of a power outage for example. The ext2 filesystem is extremely
>> unreliable, and will almost always lose data when there's a crash or power
>> outage.
>
> but then why does read/write tests over raw devices performs so bad?
> AFAIK on raw devices not filesystem, journaling, caches, etc are involved.
> _______________________________________________

Like I said before, you might not have been testing the throughput of 
the disks,
instead you may have been testing the throughput of /dev/zero.

Ken