FreeBSD and newer HDD problems ?

Mikhail Goriachev mikhailg at
Sun Jun 4 10:43:17 PDT 2006

Pavel Duda wrote:
> Hello,
> I've recently bought new big HDD (WDC RE, 320GB) and it looks like
> FreeBSD has some troubles with it when trying to transfer files over
> network.
> If I try to perform some "synthetic" test like 'dd if=/dev/zero
> of=/wdc320/testfile' then I get some decent speeds about 40MB/s. When I
> try to copy some big files from my older disk (IBM 40GB) I still have
> write about 25-27MB/s.
> Problem comes when I try to copy something to disk over network (tried
> samba, ftp) disk write speed is very low - about 5-6MB/s at max.
> When testing this issue I've start 'systat -vmstat 1' and noticed that
> my new disk is very busy (60-100%) and speed (MB/s) jumps up and down.
> If I write files with 'dd' or transfer them from disk 2 disk then write
> speed and disk load is almost constant (about 60%). When transfering
> files over network to old HDD then disk load is low (40-50%) and speed
> is constant (8-9MB/s).
> To be sure that disk it is not some kind of disk problem I've installed
> Debian 3.1r2 with same version of samba and I get 9-11MB/s transfer
> speeds (in both directions) !!
> Also it doesn't matter if I use transfer data over gigabit card or
> 100mbit card. Results are similar. FreeBSD is in avarage very very slow
> (3MB) while Debian works fine (10MB). Because my server is primarily
> used for transfer files (Samba + PDC) it is crucial for me to have
> highest transfer speeds possible and I'd like to stick with FreeBSD :-/.
> Does someone has any idea what could be wrong or how could I determine
> what causes this problem ?


This effect is normal since you're transferring files over relatively
slow network. The speed through 100Mb/s Ethernet will be around 5 or
6MB/s and probably you can't go any faster due to your hardware
limitations (switch, cables, processor, controllers and especially their

Currently there are a few active threads related to similar issues
(controllers and their drivers). You might be interested in following them:


Mikhail Goriachev

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