Franz Petri wrote: > Hi, > > I have a problem getting the performance up when writing to an external > harddisk, connected via usb 2.0. > > It shows when doing: > i) cp file_from_local_sata_hdd to_usb_hdd_formatted_with_ext3fs_or_reiserfs > ii) tar -xf file_from_local_sata_hdd > -C/directory_on_usb_hdd_formatted_with_ext3fs_or_reiserfs > iii) dd if=file_from_local_sata_hdd > of=to_usb_hdd_formatted_with_ext3fs_or_reiserfs > iv) all other stuff that incorporates writing to the disk, like creating > encfs-files on it or > trying to setup an encrypted loop device with yast on it. > > It shows on both opensuse 10.1 and 10.2, on a dual core centrino notebook > (lenovo x60s) as well as > on a dual core pentium desktop. No patched or self-built kernel or -modules > are installed, all is > pretty and default exept that all the latest packages from guru and packman > are installed via smart. > > Performance figures look like this: > > CASE 1, writing onto the local sata disk: >> dd if=/dev/zero of=tmp.txt count=1000 > 1000+0 records in > 1000+0 records out > 512000 bytes (512 kB) copied, 0.012393 seconds, 41.3 MB/s > > CASE 2, "default" writing to the usb hdd, one can replace dd with cp or tar > at will, the figures > stay the same: >> dd if=/dev/zero of=/media/usbdisk/tmp/tmp.txt count=1000 > 1000+0 records in > 1000+0 records out > 512000 bytes (512 kB) copied, 3.26417 seconds, 157 kB/s > > CASE 3, notice the increased bs: >> dd if=/dev/zero of=/media/usbdisk/tmp/tmp.txt count=4 bs=128K > 4+0 records in > 4+0 records out > 524288 bytes (524 kB) copied, 0.033982 seconds, 15.4 MB/s > > CASE 3 is what i would be expecting and what also what I get when writing to > a fat32-partition on > the external usb hdd. This also implies IMHO that there is nothing wrong with > my usb-setup as > suggested in various other postings regarding usb-performance. > > Here is an output regarding the usb-modules: > >> lsmod | grep hci > ehci_hcd 34696 0 > uhci_hcd 26892 0 > usbcore 115024 3 usbhid,ehci_hcd,uhci_hcd > > As suggested in > http://marc.abramowitz.info/archives/2007/02/17/getting-good-performance-out-of-usb-hard-drives-in-linux/ > I also tried fiddling with the value of /sys/block/sdX/device/max_sectors but > with no significant > success... > > I have created the ext3 and reiser partitions on the usb hdd with the yast > partitioner, basically > leaving everything at default settings. > > Any hints on where else to look for the cause of this poor performance? > > My workaround right now is to "copy" with: > tar -cf - file_from_local_sata_hdd | tar -xf - -b2000 > -C/directory_on_usb_hdd_ext3fs_or_reiserfs > > I am using -b2000 hereby to be able to do larger blocksized writes. > > Regards, > > Franz. > > > I use an external drive on 10.2 with no problem. I get about 20 MB / sec. I just let te system mount properly and t seems to work without any problems. Can you confirm if it is operating. Can you confirm that the device is mounted as a USB 2.0 high speed device (480 Mb/sec) as oppose to USB 2.0 (12 Mb/sec). Try using the USB device program.
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. -- Joseph Loo [EMAIL PROTECTED] -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
