Mailinglist Archive: opensuse (3566 mails)

[Franz Petri <f.petri@xxxxxxxxxxxxx>]

Hi,

thanks for your replies and sorry for my delay in answering.

Joseph Loo wrote:
> Franz Petri wrote:
>> Hi,
>>
>> I have a problem getting the performance up when writing to an external harddisk, connected via usb 2.0.

...

> Another item check to see how it is mounted. Do a cat /proc/mounts. this will
> help determine if you are running synch versus asynch. Synch slows the operation
> significantly.
> 

It seems that synch mode was indeed the cause for this.

~> cat /proc/mounts
rootfs / rootfs rw 0 0
udev /dev tmpfs rw 0 0
/dev/hda2 / ext3 rw,data=ordered 0 0
proc /proc proc rw 0 0
sysfs /sys sysfs rw 0 0
debugfs /sys/kernel/debug debugfs rw 0 0
devpts /dev/pts devpts rw 0 0
/dev/hda3 /home ext3 rw,data=ordered 0 0
securityfs /sys/kernel/security securityfs rw 0 0
/dev/sda2 /media/disk reiserfs rw,sync,nosuid,nodev 0 0
/dev/sda1 /media/disk-1 vfat
rw,nosuid,nodev,noatime,uid=1003,fmask=0022,dmask=0022,codepage=cp437,iocharset=iso8859-1,utf8 0 0
~>
~> dd if=/dev/zero of=/media/disk/tmp/tmp.txt count=1000
1000+0 records in
1000+0 records out
512000 bytes (512 kB) copied, 2.57634 s, 199 kB/s

I usually let kde do all the mounting of external SD-cards, usb-drives, cd-rom, ect.
So I went to "drive properties" via sysinfo:/ and unchecked "Sync", then "safely removed" the usb
disk and mounted again (via kde-interface).

This is what it looks like now:

~> cat /proc/mounts
rootfs / rootfs rw 0 0
udev /dev tmpfs rw 0 0
/dev/hda2 / ext3 rw,data=ordered 0 0
proc /proc proc rw 0 0
sysfs /sys sysfs rw 0 0
debugfs /sys/kernel/debug debugfs rw 0 0
devpts /dev/pts devpts rw 0 0
/dev/hda3 /home ext3 rw,data=ordered 0 0
securityfs /sys/kernel/security securityfs rw 0 0
/dev/sda1 /media/disk-1 vfat
rw,nosuid,nodev,noatime,uid=1003,fmask=0022,dmask=0022,codepage=cp437,iocharset=iso8859-1,utf8 0 0
/dev/sda2 /media/disk reiserfs rw,nosuid,nodev 0 0
~>
~> dd if=/dev/zero of=/media/disk/tmp/tmp.txt count=1000
1000+0 records in
1000+0 records out
512000 bytes (512 kB) copied, 0.0472442 s, 10.8 MB/s
~>

This is at least a reasonable magnitude of the transfer rate.
So the problem is solved for now for me.

BUT: As google finds the risk of data loss being the biggest drawback of the async mode, some
questions remain:

- Is "safely remove" via kde the way to go at all to finish off all transfers?
- Can I trust kde to properly flush and umount everything when shutting the PC down, or do I have to
"Safely remove" everytime before I shut down?
- Is there a certain idle time period after which I can assume no harm to my data, even when I just
unplug the usb drive without "safely remove"?

Thanks,

Franz.