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From: Dominik & Co on 19 Mar 2010 09:45
Hi all,

Debian 5.0 (Lenny), Gnome, kernel 2.6.30.
SD card writer achieves low write speed, both internal
"all in one" and pendrive-like external- usb connected.

I had decided to turn on async mode while mounting by HAL.
This is my nosync.fdi file located in
/usr/share/hal/fdi/policy/95userpolicy

<?xml version="1.0" encoding="ISO-8859-1"?> <!-- -*- SGML -*- -->
<deviceinfo version="0.2">
<device>
<!-- disable sync for mount -->
<match key="block.is_volume" bool="true">
<match key="volume.fsusage" string="filesystem">
<match key="@info.parent:storage.bus" string="usb">
<merge key="volume.policy.mount_option.sync" type="bool">false</merge>
</match>
</match>
</match>
</device>
</deviceinfo>

And it worked, external HDD and pendrives got quite good write speed.
But not SD cards...

The card itself has not so bad read and write speed:

debianek-dom:/home/monika# time dd if=/dev/sdb1 of=/home/monika/karta.img
skopiowane 1967058432 bajty (2,0 GB), 129,525 s, 15,2 MB/s
real 2m9.575s
user 0m1.704s
sys 0m25.382s
debianek-dom:/home/monika# time dd if=/home/monika/karta.img of=/dev/sdb1
skopiowane 1967058432 bajty (2,0 GB), 530,707 s, 3,7 MB/s
real 8m50.828s
user 0m1.632s
sys 0m24.038s

But when I want just to copy some files, things get worse:

(sync mode)
debianek-dom:/home/monika/roboczy# mount /dev/sdb1 -o sync,remount
monika(a)debianek-dom:~/roboczy$ time cp *.avi /media/disk
real 18m11.096s
user 0m0.200s
sys 0m24.330s

(async mode-now default one)
debianek-dom:/home/monika/roboczy# mount /dev/sdb1 -o async,remount
monika(a)debianek-dom:~/roboczy$ time cp *.avi /media/disk
real 34m42.870s
user 0m0.072s
sys 0m10.285s

monika(a)debianek-dom:~/roboczy$ cat /proc/mounts
(cut)
/dev/sdb1 /media/disk vfat
rw,nosuid,nodev,relatime,uid=1000,fmask=0022,dmask=0000,allow_utime=0022,codepage=cp437,iocharset=utf8
0 0

What is wrong? Wherever I looked, the hint to improve SD card
write speed is turning on async mode...

Thanks in advance for any tips. Maybe should I mount SD cards only
in sync mode? But how -not by hand?

Now I just loop mount card image, copy necessary
files and write image to the card. Somehow wearisome...

--
Dominik (& k�pany)
"Wszyscy chc� naszego dobra. Nie dajmy go sobie zabra�." (S.J. Lec)
Wyra�am wy��cznie prywatne pogl�dy w oparciu o Art. 54 Konstytucji RP

--
Dominik (& k�pany)
"Wszyscy chc� naszego dobra. Nie dajmy go sobie zabra�." (S.J. Lec)
Wyra�am wy��cznie prywatne pogl�dy zgodnie z Art. 54 Konstytucji RP
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