Can't get past 10 mbyte/s with freenas

[KalleDK]

Hi

I can't write with more than 10 mbyte/s to my hdd (dd zero to disk 16m)

ada0 at ahcich0 bus 0 scbus0 target 0 lun 0
ada0: <WDC WD20EARS-00MVWB0 51.0AB51> ATA-8 SATA 2.x device
ada0: 300.000MB/s transfers (SATA 2.x, UDMA6, PIO 8192bytes)
ada0: Command Queueing enabled
ada0: 1907729MB (3907029168 512 byte sectors: 16H 63S/T 16383C)

If I boot in a normal 8.2 fixit shell (from the install media) it doesnt see it as ada0 but da4 - and there I can dd with 150 mbyte/s

I can't seem to grasp why I cant get past the 10 mbyte/s via freenas

The bios is set to ACHI

(windows also gives 100mbyte+/s)

Edit: Tried to make a clean 8.2 install and enable ACHI in that.. and boom they went down to 10mbyte/s seems to be the "driver" or something... (not that good at freebsd yet)

 

[matthewowen01]

how is your disk formated, zfs, ufs?

what is the exact dd command you used?

 

[KalleDK]

dd if=/dev/zero of=/dev/ada1 bs=16m

Well after some tests today I got following

FreeNAS 8.0 latest binary = 10 mbyte/s with AHCI (ada1)
FreeBSD 8.2 latest binary = 150 mbyte/s without AHCI (ad2)
FreeBSD 8.2 latest binary = 10 mbyte/s with AHCI (ada1)
FreeBSD 8.2 latest src = 150 mbyte/s with AHCI (ada1)

Looks like it is a driver problem (or something) that have been fixed in the latest src of 8.2..

So I just have to wait until FreeNAS comes to that version.

 

[matthewowen01]

so your writing 16MB directly to the device. but it looks like your disk is ada0 and you're writing to ada1. you are also writing a very small file your disk probably has a 16MB cache on-board so your test is invalid. i can read and write a 2 GB file at 6GB/s because it only uses the cache.

create a storage pool first, preferable zfs, then write to it. Instead of your dd command, try this:

dd if=/dev/zero -of=/mnt/YOURPOOL/file.dat bs=1024k count=20k

this will utilize zfs, exceed any cache or buffer and give you a real measure of speed over time. then reverse the process and read from that file and write it to /dev/null

let me know how that works.

 

[KalleDK]

No I'm writing in 16mb blocks... (this dd would fill the hdd if I don't stop it with ^c), and I'm always making it run to at least 10 gb

the ada1 and ada0 confusing is due to i got 4 equal drives ada0-3 same disk but all with the same "problem" - forgot to post that


If i make a raidz pool when the disks only can do 10 mbyte/s i get around 30mbyte which seems corecct (4 disks at 10 mbyte/s)

If i make a raidz pool when the disks can do the 150 mbyte/s i get 210 mbyte/s and I think its my processor limiting this due to checksum etc.

 

[matthewowen01]

oops you are so right about that, i haven't used dd that way in a long time.

what are your system specs?