https://bugs.kde.org/show_bug.cgi?id=342056
--- Comment #43 from Nick <nick.craig....@gmail.com> --- (In reply to empyreal from comment #42) > I need to figure out whether it is hardware issue or not. > It’s some sort of interface buffer problem, because changing settings in > Windows helped for short period of time. > > Windows. Mount slow. Copy slow. > Offline and disconnected drive. Waited few min. > Connected drive and Online. Mount slow. Copying slow. > Device Manager => Volumes => Populate. Data received but no help. Mount > slow. Copy slow. Very long Shutdown. > > Windows. Waited few min. Connected USB drive. Mount slow. Copy slow. > Noticed that folders, copied on Kubuntu open with lag. Formatted USB drive > just in case. Switched buffer settings in Windows. Sometimes it helped USB > drive to copy faster, but for short period of time. Speed was unstable. > > Made few Short DST of SAS-SCSI-FC until device passed in SeaTools. > Rescanned. USB 1394 showed up. Copy slow. > Disconnected drive. Restarted Windows. Connected drive. > Copying started fast, then became slow. > > Device Manager => Volumes => Populate. Volume data received. Copying became > faster. I have no idea how it works, but it shows some effect. > Started copying. Starts very slow and then goes fast. > > Reboot with USB drive. Stuck. Unplugged drive. Rebooted Windows. > Connected USB drive. Started copying video files in Total Commander. Started > fast then speed dropped to 1 MB/s. > > Now drive steadily behaves like this: when connected, starts fast copy, the > slows down to … KB/s. Drive slows boot and restart. That initial burst is actually normal, but dropping to 1MB/s is classic behaviour when you have a bad drive or controller that's generating I/O errors. The reason for the initial burst is that when the I/O writes first start, the operating system is filling the I/0 buffer in CPU RAM which it does very much quicker than sustained disc I/O then once there is no more space in memory you then see the true I/O speed and if you have a bad drive or controller you will see it drop way down. For a spinning disc I'd expect anything from 30MB-160MB/sec. SSD maybe 200-400MB/s. So say you have 8GB CPU memory you would expect to see that initial burst drop off after you had copied maybe 4-6GB of files. As you are seeing 1MB/s after the initial burst I would say you do seem to have a hardware fault. Like I mentioned earlier using ShredOS will confirm that. Assuming you have a backup of everything on that disk. By using ShredOS if you see the same effect i.e an initial burst (which is expected as explained above) but then it drops to 1MB/s that would confirm to me you have a hardware fault. Even on a 20 year old spinning disc you would see 20-35MB/s 30 seconds or so after that initial burst. However if you don't see 1MB/s but see a sustained throughput that is much higher, then you most likely have a software issue. Until you run ShredOS you won't be able to isolate the problem. I'd also do a grep on /var/log/ messages and also Windows event log to look for I/O errors. -- You are receiving this mail because: You are watching all bug changes.
