FreeBSD and poor ata performance

fandino fandino at
Fri Oct 15 10:41:17 PDT 2004

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.

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